Biology

Science

Term-I

B.S. TomarM.Sc., Ph.D.

~GlobalPublications Pvt. Ltd.

Class-IX

Ii:i

a:t

(10 Periods)

SyllabusClass - IX

Course Structure

First Term Marks: 90

Units MarksI. Food 13

II. Matter - Its nature and behaviour 29III. Organisation in the living world 18

IV. Motion, force and work 30

Total 90

Theme: Food

Unit: Food

Plant and animal breeding and selection for quality improvement and management; use of fertilizers,manures;- protection from pests and diseases; organic farming.

Theme: Materials (22 Periods)Unit: Matter - 'Nature and behaviour

Definition of matter; solid, liquid and gas; characteristics - shape, volume, density; change of state-melting(absorption of heat), freezing, evaporation (Cooling by evaporation), condensation, sublimation.

Nature of matter: Elements, compounds and mixtures. Heterogeneous and homogenous mixtures, colloidsand suspensions.

Theme: The World of The Living (22 Periods)Unit: Organization in the living world

Cell- Basic Unit of life: Cell as a basic unit of life; prokaryotic and eukaryotic cells, multicellular organisms;cell membrane and cell wall, cell organelles; chloroplast, mitochondria, vacuoles, endoplasmic reticulum,golgi apparatus; nucleus, chromosomes - basic structure, number.

Tissues, Organs, Organ System, Organism.

Structure and functions of animal and plant tissues (four types in animals; meristematic and permanenttissues in plants).

Theme: Moving Things, People and Ideas (36 Periods)Unit: Motion, force and work

Motion: Distance and displacement, velocity; uniform and non-uniform motion along a straight line;acceleration, distance-time and velocity-time graphs for uniform motion and uniformly accelerated motion,equations of motion by graphical method; elementary idea of uniform circular motion.

Force and Newton's laws: Force and motion, Newton's laws of motion, inertia of a body, inertia and mass,

momentum, force and acceleration. Elementary idea of conservation of momentum, action and reactionforces.

Gravitation: Gravitation; universal law of gravitation, force of gravitation of the earth (gravity), accelerationdue to gravity; mass and weight; free fall.

Continuous and Comprehensive EvaluationFormative Assessment• Formative assessment is atool used by the teacher to continuously monitor student progress in anon-threatening supportive

environment.

• It involves regular descriptive feedback, achance for the student to reflect on the performance, take advice and improve upon

it.

• It involves students being an essential part of assessment from designing criteria to assessing self or peers.

• If used effectively, it can improve performance tremendously while raising the self esteem of the child and reducing theworkload of the teacher.

Summative Assessment• Summative assessment is carried out at the end of acourse of learning.• It measures or 'sums-up' how much astudent has learned from the course.• It is usually agraded test, Le., it is marked according to a scale or set of grades.

Grading System

Scholastic A

Marks Range Grade Attributes Grade Point

91-100 A1 Exceptional 10.0

81-90 A2 Excellent 9.0

71-80 B1 Very Good 8.0

61-70 B2 Good 7.0

51-60 C1 Fair 6.0

41-50 C2 Average 5.0

33-40 0 Below Average 4.0

21-32 E1 Need to Improve

00-20 E2 Unsatisfactory

Scholastic B

Grade

A+

A

B+

B

C

Promo1j'on is based on the day-to-day work of the students throughout the year and also on the performance in the terminalexami a ·on.

*Firs e -FA1 (10%) +FA2 (10%) +SA1 (30%)

~SeGofld term -FA3 (10%) + FA4 (10910) + SA2 (30%)

Formative Assessment (FA) 1+2+3+4

Summative Assessment (SA) 1+2

=40%

=60%

The system being implemented will have the following advantages:

• It will minimise misclassification of students on the basis of marks.

• It will eliminate unhealthy cut-throat competition among high achievers.

• It will reduce societal pressure and will provide the learner with more flexibility.

I will lead to afocus towards abetter learning environment.

Chapter: One

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Introduction

Fig. 1.2Slice of cork showing cells

Fig.11Robert Hooke's rricroscope

PQ ~ Q __O__Q

• Take a small piece from an onion.• Use a forcep to separate a peel from its inner layers (concave side).• Put this inner layer immediately in a watch-glass containing water. This will prevent the

peel from getting folded or dry.

There are over 1.7 million kinds of organisms. They all show an enormousdegree of diversity of form and size. Yet they have an underlying unity in their basicstructure and process. All living structures we see around us are essentially madeup of numerous compartments (microscopic units) called cell. Robert Hooke (1665)is credited with the discovery of cell. When Hooke made his chance observationthrough a -self-designed microscope, he observed a honeycomb-like pattern in avery thin slice of cork (Fig. 1.2).

This honeycomb-like structure consisted of a thick wall enclosing box-likecompartments. Hooke called these boxes, cells. Actually, cell is a Latin word for 'asmall room'. This may seem an insignificant incident, but it held a lot of importancein the history of science. This was the very first time that someone had observed thatliving things appear to consist of such separate units. The use of the word 'cell' todescribe the unit is prevalent till this day in biology.

Let us perform an activity to find out cells.

8ctivig1

1='9 • _3 Prep, ~ng ,,,rporaf'/ mou, I a onion lee,

• Now, take a glass slide, put a drop ofclean water on it and transfer the small piece of onionpeel from the watch-glass on to the slide. Make sure that the peel is perfectly flat on the slide.

• For this, you may need a thin camel hair paintbrush.• Put a drop of iodine solution on the piece of onion peel.• Gently place the cover-slip onto the slide using a mounted needle to avoid air bubbles.• This is how you prepare a temporary mount of onion peel. For observation place the slide

onto the stage of the microscope.• Carefully observe the slide under microscope using the low power and high power of a

compound microscope.

The Fundamental Unit of Life 5

Eyepiece --.;#'f!/:""t

Coarseadjustment

Fine ---"'I'adjustment

Clip---

Stage height -----.;~adjustment

:;:.---- Tube

Objective lens___ (high power)

7...~--- Objective lens(low power)

MICROSCOPE

Cells are very small in size and cannot be seen bythe naked eye. For observing a minute cell oneneeds a microscope. Leeuwenhoek prepared. alight microscope which is comparable to today'scompound microscope. The object (specimen) ona glass slide is kept on a stage, bearing a centralhole under an objective lens. Light is reflectedthrough the specimen with the help of a mirror anda condenser from below the stage. Through the eyepiece one can see the magnified image of an object.Eye piece is located at the top. Focussing is usuallydone by the adjustors (coarse and fine) fitted in themicroscope. Eye piece and objectives of high andlow powers are available.

Fig. 1.4 Compound microscope and its parts

Cell wallI::!::=i!-- Cytoplasm

Nucleus

Vacuole

Fig. 1.5 Cellular structures of onion peel

What do you observe when you look through the lens? Can you drawthe structures that you are able to see through the microscope in yourobservation sheet? Does it look like the Fig. 1.5.

When you try preparing temporary mounts of peel of onions ofdifferent sizes, you will find that all contain similar small struc;tures.

These small structures which you see in an onion peel are the basicbuilding units.called cells. ot only onions, but all organisms which you seearound are made up of cells.

• Cell is the structumland functional unitof life.

• A cell arises from apre-existing cell.

Discovery of CellThe term 'cell' was used by Robert Hooke in 1665. He observed cells in a

piece of cork under a primitive microscope. In 1674, Anton von Leeuwenhoekdiscovered free cells like bacteria, protozoa, red blood cells and sperm with the helpof improved microscope. Robert Brown in 1831 discovered the nucleus in the cells.In 1839, Johannes Purkinje named the fluid content of the cell as protoplasm. In1892, O. Hertwig proposed that cell is a mass of 'protoplasm' .

Cell Theory. All plants and animals are composed of cells and that the cell is the basic unit of

life, ,vas presented by two biologists-Matthias Jacob Schleiden (German Botanist)and T. Schwann (German Zoologist), in 1839.

In 1855, R. Virchow further expanded the cell theory as, "Omnis cellulae acellula", i.e., all cells arise from pre-existing cells. Soon thereafter in 1866, Haeckel,established that nucleus stores and transmits hereditary traits. In 1880, Fleminghad shown that cells ensure continuity between one generation and another by

6 The Fundamental Unit of Life

the mechanism of mitosis. Waldeyer in 1890 described the precise division of thechromosomes.

Thus, the modern version ofthe cell theory is as follows:

(i) All living organisms are composed of cells and their products.

(ii) Cell is the structural and functional unit of life.

(iii) All cells arise from pre-existing cells.

(iv) The smallest unit of life is the cell, i.e., every organism starts its life as asingle cell.

With the discovery of electron microscope in 1940, it was possible to observeand understand the complex structure of the cell and its various organelles. Thefirst electron microscope was designed by Knoll and Ruska in 1932.

Unicellular and Multicellular OrganismsWe cannot imagine an organism that is not formed of a cell. Organisms may be

made up of one or more cells. If the organisms are made up ofa single cell, they arecalled unicellular organisms (uni-single), e.g., Amoeba, Chlamydomonas, Parameciumand bacteria. On the other hand, if organisms are made up of many cells, they arecalled multicellular organisms (multi-many).

The multicellular organisms may be made up of few cells (e.g., some algaland fungal forms) to several million cells (e.g., human being, tree, whale, etc.).In a multicellular organism certain cells become specialised to perform a specificfunction and thus division of labour is established among different groups of cells.The group of cells having a common origin and performing a similar but specificfunction constitute a tissue (e.g., muscles). Several different types of tissues may joincollectively to form an organ which carries out one or more specific functions (e.g.,kidney, liver, brain). Several organs are inter-related to perform a specific functionand thus, constitute an organ system (e.g., digestive system, circulatory system,nervous system, etc.).

The life of every multicellular organism begins as a single cell. However, theunicellular organisms, complete their entire life cycle as a single cell. In others,

.an increase in the number of cells takes place in the course of life. All the cells ofour body come from a single cell, zygote, which divides continuously to form ourmulticellular body. Thus, all cells come from pre-existing cells.

The cells are not only the building blocks of our body, they are functionalunits of life too. Each living cell has the capacity to perform certain basic functionsthat are performed by all living forms. If you study Fig. 1.10, you will observe thathuman beings have different types of cells like sperm, blood cell, bone cell, musclescell, nerve cell, fat cell, etc. We know that there is division of labour in multicellularorganisms, e.g., human beings. It means that different parts of the human bodyperform different functions. The human body has a heart to pump blood, a stomach

.. to digest food and so on. Likewise, in a human body, the division of labour is alsoseen inside a single cell. In fact, each cell has got certain specific components insidethe cell, called cell organelles. Each type ofcell organelle performs a special function,e.g., protein synthesis, food synthesis, clearing up the waste material from the cell,etc. Thus, all the activities of an organism are present in miniature forms in each andevery cell. So, a cell is able to live and perform its function due to these organelles.These organelles together constitute the basic unit called the cell. Therefore, the cellcan be called a basic unit of life and the structural unit of an organism

Fig. 1.6 Electron microscope

The Fundamental Unit of Life 7--------------------------t.~~~~--,.-.

Cell is made of a living substance called protoplasm. (proto = first, plasma= liquid). The protoplasm is made up of four elements namely carbon, hydrogen,nitrogen and oxygen. Other elements such as phosphorous, sulphur and calciumare also present. These elements combine to form compounds like water, proteins,fats, carbohydrates and nucleic acid (DNA and RNA), etc.

activi~2

• Try preparing temporary mounts of leaf peels, onion root zip. lOu can also take leaf ofmaize, mustard or tmdescantia for this purpose.

• Take a red-coloured tmdescantia leaf

• Take out a small peel fTOm the lower surface of the leaf with a quick jerk.

• Prepare temporary mount of this peel.

• Place it under the microscope and observe it.

• lOu will observe that each cell is filled with red-coloured cell sap.

activi~3

• Keep a drop of your blood on a glass slidewith the help ofa sterile needle.

• Smear the blood over- the centre of a slidewith the help of another slide.

• Put a drop of methylene blue stain on top ofthe smear and cover the slide with a coverslip.

• When dry, observe the slide first under lowpower and then under high power microscope.

• Identify and draw its structure. ~ ?"" .,...., .r-· ~._.. ~_ .ft

Platelets Red blood corpuscles

~ g. ~ ~ Ce 5 .~ huma~ blood

8

You will observe the blood cells in the slide as shown in Fig. 1.7.

After performing the above activity you will be able to give answer to thefollowing questions.

(i) Do all cells look alike in terms of their shape and size?

(ii) Could you find differences among cells from different parts of a plant body.(iii) \'\That similarity could you find?

Answers:

(i) All cells of a multicellular organism are of different shapes and sizes and cellsof different organisms are different.

(ii) The different parts of a plant body are different in shape, size and structure.

(iii) The similarities among all the cells of higher organisms are that they containplasma membrane, a cytoplasm which contains cell organelles and a nucleus.

Prokaryotic and Eukaryotic Cells

I (a) Prokaryotic cell

Organisms with cells in which the nuclear material is not bounded by a definitenuclear membrane are called prokaryotes, e.g., bacteria and blue-green algae.

The Fundamental Unit of Life

These are the most primitive cells. Nuclear material consists of a single chromosomewhich is in direct contact with the cytoplasm. In a prokaryotic cell, other membranebounded organelles, such as mitochondria, endoplasmic reticulum, lysosome,chloroplast, golgi bodies, etc., are also absent. However, ribosomes are present insuch cells.

Proteincoat~

DNA~(\~:'J", \jor \ '-/ I

RNA ~

(a)

, DNA

--\~ L~ I Cytoplasm

(b)

..-----. ~ Plasmamembrane

'. Cytoplasm

CJ+=Nuclearmembrane

.0') \ Nodoo'",

V / Nucleoplasm

(c)

Fig. 1.8 (a) Virus. (b) Prokaryotic ceil of bacteria. (el Eukaryotic cell of animal

I (b) Eukaryotic cell

These are advanced and complete cells in which the nucleus has a definitenuclear membrane. In eukaryotic cells, other membrane-bounded organelles, suchas mitochondria, ribosome, lisosome, E.R., chloroplast, golgi body are present.

Viruses do not easily fit in the definition of a cell and they are often describedas 'living chemicals' or as cellular forms which are degenerated through parasitism.Virus is an infectious, sub-cellular and ultramicroscopic particle which divides onlyin the host cell and can be transmitted by injection and causes characteristic reactionsin the host cell. Viruses lack internal organisation which is the characteristic of acell. The viruses living within the bacteria are called bacteriophages. The cells ofbacteria are different from animal and plant cells. Bacterial cells are prokaryoticcells, whereas plant and animal cells are eukaryotic. The important differencesbetween prokaryotic cells and eukaryotic cells have been given in Table 1.1.

Table 1.1 Differences between Prokaryotic and Eukaryotic cells

S.No. Feature Prokaryotic cells I Eukaryotic cells

1. Size Generally small, 1- 10 !-Lm Generally large, 5-100 !-LID

2. Cell Non-cellulosic Cellulosic in plants only

3. Cell organelles Absent except ribosomes Present, e.g., mitochondria,endoplasmic reticulum,Golgi apparatus, lysosomes,peroxisomes, plastids, etc.

4. Nuclear Absent. Nucleoid or nuclear Present. DNA is surroundedmembrane region is not surrounded by by a nuclear membrane

nuclear membrane, i.e., DNAis n<rked

5. Chromosome Single More than one

6. Nucleolus Absent Present

7. Cytoskeleton Absent Present

8. Cell division By fission or budding (amitosis) Mitotic or meiotic

The Fundamental Unit of Life I VI( 11~ 'J

FORMATIVE ASSESSMENTFA 1.1 Multiple Choice Questions

Select the right choice:

1. The basic structural and functional unit of all living organisms is alan

(a) organ (b) tissue

(c) cell (d) proteins

2. The cell was discovered by(a) Robert Brown (b) Leeuwenhoek

(c) Robert Hooke (d) Flemming3. An undefined nuclear region containing only nucleic acid in prokaryotes is

known as

(a) nucleus (b) nucleolus

(c) cellulose (d) none of these

4. The organism lacking nucleus and membrane-bound organelles are

(a) prokaryotes (b) dipleids

(c) eukaryotes (d) none of these

5. The only cell organelle present in prokaryotic cell is

(a) mitochondria (b) ribosome

(c) plastids (d) lysosome

FA 1.2 Match the Following

Match the terms given in column I to their meanings in column II.

Column I Column II

(a) First electron microscope (i) Only ribosomes present

(b) Nucleus (ii) Knoll and Ruska

(c) Prokaryotes (iii) Robert Brown

(d) Cell theory (iv) An undefined nuclear region in prokaryotescontaining only nucleic acid

(e) Nucleoid (v) Schleiden and Schwann

FA 1.3 Complete the Table

Complete the following table by writing appropriate answer.

10

Feature

Cell wall

Cell organelle

Nucleolus

Cell division

Prokaryotic cell

Non-cellulosic

Absent

Eukaryotic cell

Present, e.g., mitochondria, endoplasmic,reticulum, Golgi apparatus, lysosomes,plastids, etc.

Mitotic or meiotic


FA 1.4 If I SA ••••• ?"' orksheet

Pretend yourself to be an eukaryotic cell and answer the following questionsaccordingly.

1. Write your defining features with examples.

2. Differentiate between prokaryotic and your cell.

3. What is the difference between your nucleus and prokaryotic cell's nucleoid.4. Write down the name of your cell organelles..

FA 1.5 Activity-based ~'Vorksheet

Observe permanent slide of onion root tip or peels of onions of different sizes.After carefully observing the permanent slides answer the following questions.

1. Do all cells look alike in terms of shape and size?

2. Do all cells look alike in structure?

3. Could we find differences among cells from different parts of a plant body?4. What similarities could we find?

Cell

Definition of cell: According to Loewy and Siekevitz.(1963), cell is a unit ofbiological activity surrounded by a selectively permeable membrane and capable ofself reproduction.

I Cell shape

The shape of the cells are related to their functions. It may be variable orfixed. Cell shape is variable like Amoeba and leucocytes (white blood cells). Amoeba(single-celled animal) during locomotion changes its shape; similarly leucocytes alsochange their shape by producing pseudopodia and become irregular in shape.

Contractilevacuole

Food vacuole

Water globules

Crystals

0'/1Nucleus

" Plasmalemma~

"\ ----- Endoplasmo

:: Hyalinecap

Fig. 1.9 Amoeba

In most cases the shape of a cell is fixed, e.g., plants and animals (includingParamecium, Euglena, etc). In case of unicellular organisms, the cell shape is maintained


by a tough cell membrane (e.g., Paramecium) and exoskeleton (e.g., Elphidium, Polystomella).

In case ofmulticellular organisms, the shape ofthe cells depends on their functionaladaptations and partly on surface tension and viscosity of the protoplasm, mechanicalaction exerted by adjacent cells and turgidity of the cell membrane. Therefore, cellsmay have diverse shapes, such as spherical (eggs cells), elongated (nerve cells), branched(pigment cells of skin), discoidal (RBC) and so on. (see Fig. 1.10).

Fat cell

Cells liningintestinal tract

Neuron inbrain

-~~~Sperm •

Ovum

Bloodcells

Fig. 1.10 Examples of various types of cells

Fig. 1.11 Acetabularia

I Cell size

The size of the cells varies greatly in plants and animals. Some cells are visibleto the naked eye like egg of ostrich (18 em) and ovule of Cycas. Some nerve cells ofhuman beings have a metre long 'tail'- axon. A single-celled algae AcetabulaTia is10 ,urn in height (see Fig. 1.11) and sclerenchyma cells (fibre cells) of Manila hempare more than 100 em in length. Most prokaryotic cells are in the range of 1 to10,um (one micrometre is one thousandth ofa millimetre). Most eukaryotic cells aremicroscopic measuring 10-100 mm. The size of a unicellular organism is larger thana typical cell of multicellular organism, e.g., Amoeba pTOteus is the biggest among allunicellular organisms. Its length is 60 ,urn (0.6 mm). In multicellular organism, thesize of cells ranges from 20-30 ,urn. The smallest cells are found in bacteria (0.2,um0.1 ,urn), e.g., Mycoplasma gallisepticum, that is an organism intermediate between thevirus or bacteria. Its size is about 0.1 ,urn.

I Cell volume

The cell volume, in general, is fairly constant for a particular cell type and isindependent of the size of the organism. For example, kidney and liver cells areabout the same size in the mouse, horse and bull. The difference in size of organismsdepends on number of cells only and not on the volume of the cells. Therefore, thecells of an elephant are not larger than those of other tiny animals or plants. Due tothe large number of cells present in the body, the elephant becomes large.


~ .._--------~~----------------

I Cell number

The cell number in an organism varies with the size of organism. Unicellularorganisms have a single cell. In multicellular organisms, the cells are indefinite. InPandorina, number of cells are 8, 16,32 or 64 and in Eudorina 16,32 or 64. In man,the number of cells is about 100 trillion (l014

).

Structure of a CellIfyou observe a cell under the microscope, you will come across three features in

almost every cell- plasma membrane, nucleus and cytoplasm. Each cell has an outerboundary called plasma membrane. Inside the plasma membrane lies the cytoplasm.Various cell organelles are suspended in the cytoplasm. All activities inside the celland interaction of the cell with its environment are possible due to these features. Inaddition to these organelles, nucleus is also seen under the microscope.

Centrioles

___ I"~ :/ Lysosome

~ '..... Microtubules

~. • ;.~"' Smoothendoplasmic

reticulum

Pinocytic vesicle ;;o( " ',"{

Mitochondrion (: 'J:/~

Golgi body \:a (h~'

!N::::p,rn f .,~NUCleus .. ,:'" 6~U¥.

Nuclear~ _ ~~ "S7~/lJ . :'1 Rough .membrane '2'J'/. '.!' '" '-=--'. I endoplasmic

reticulum

Pinocytic vesicle "< ... '~.forming

Fig. 1.12 An'mal eel

Ribosomes

C'9 1.i3 Plant ce


I (A) Plasma membrane or cell membrane

Being a discrete 'unit of life' every cell is bounded by an extremely delicatemembrane which separates the cell from its non-living surrounding (extracellularmedium) and thus, provides a separate identity to the cell. This membrane is calledplasma membrane (cell membrane or plasmalemma).

Structure

Plasma membrane is a living, thin, delicate, elastic, selectively permeablemembrane. It is about 7 nm (70 A) thick. We can observe it only through an electronmicroscope. Chemical analysis has shown that the membrane contains seventy fiveper cent phospholipids. In addition, the membrane contains proteins, cholesteroland polysaccharides.

In 1972, Jonathan Singer and Garth Nicholson suggested a model, called fluidmosaic model for explaining the ultra structure of plasma membrane. Accordingto them, membrane is a lipid bilayer having integrated protein molecules. Themembrane is semifluid and dynamic in nature. The lipid and protein help inperforming transport movements. Two types of protein distinguished are:

(i) Intrinsic proteins or Integral proteins

(ii) Extrinsic proteins or Peripheral proteins

Intrinsic proteins: These are completely span on the lipid bilayers.

Extrinsic proteins: These are either on the outer surface or on the innersurface of the lipid membrane.

This model of membrane has been described as 'a number of protein icebergsfloating in the sea oflipids'. This model was the most acceptable one.

Branching carbohydrate portion ofprotein which acts as an antigen

I

Hydrophobic tails 0

phospholipid molecules

Intrinsic protein moleculespanning the phospholipid layer

Pore Extrinsic protein moleculelying on the surface

Fig. 1.14 Fluid mosaic model of plasma membrane

Functions

The plasma membrane permits the entry and exit of some materials in the cell.It also prevents movement of some other materials. Therefore, the cell membraneis called selectively permeable membrane. Now, let us find out how the movementof substances takes place across the cell. How do substances move in and out of thecell?

Some substances such as carbon dixoide (C02 ) and Oxygen (02) can moveacross the cell membrane by the process of diffusion. These substances are of

• I I ~14 The Fundamental Unit of Life

very small size, therefore, diffuse readily through the phospholipid layer of cellmembrane. To understand this process better, let us perform an activity.

activity 4• Take a glass halffilled with clean water.• Put a few drops of any coloured fluid in it. Observe it carefully.• What do you see? Does the water of the glass get uniformly coloured at once?

You will observe that the water takes the colour uniformly throughout thebeaker. This is due to a process called diffusion. This is spontaneous movement ofa substance from a region of high concentration to a region where its concentrationis low.

Diffusion

Diffusion is the movement of molecules of any substance from a region ofhigher concentration to lower concentration. This is because of the natural tendencyof a substance to spread uniformly in the dispersion medium by random movementof its molecules and ions. Diffusion is faster in the gaseous phase than in liquids andsolids.

Something similar happens in the cells too, for example, when a gas likecarbon dioxide (that is the waste product of respiration) gets accumulated in highconcentration inside the cell. In the cell's external environment, the concentrationof CO2 is low as compared to that inside the cell. As soon as there is a differenceof concentration of CO2 between inside and outside of a cell, CO2 moves out ofthe cell, i.e., from a region of high concentration to a region of low concentrationthrough the process of diffusion. In the same way, 02 enters the cell by the processof diffusion when the concentration of 02 inside the cell decreases. Thus, diffusionplays an important role in exchange of gases between the cells and its externalenvironment. Similarly, water molecules also diffuse through the plasma membraneand this is called osmosis.

Osmosis

The movement of water molecules through the selectively permeablemembrane is called osmosis.

The movement of water across the plasma membrane is also affected by theamount of substance dissolved in water. Thus, osmosis is the passage of water from aregion of high water concentration through a semipermeable membrane to a regionof low water concentration. Therefore, osmosis can be defined as the diffusion ofwater or solvent through a semipermeable membrane from a region of low soluteconcentration to a region of high solute concentration.

Let us see what will happen to an animal cell or a plant cell when placed in asolution of sugar or salt. One of the following three things could happen:

1. When the medium surrounding the cell has a higher water concentration thanthe cell, meaning that th~ outside solution is very dilute, the cell will gain waterby osmosis. Such a solution is known as a hypotonic solution

In such a solution, water molecules are free to pass across the plasma membranein both the directions, but more water molecules come into the cell than theyleave. The net (overall) result is that water enters the cell. The cell is likely toswell up.

r::::::~=~'n

t,J/\ I(~

Fig. 1.15 Cells

Diffusion into cell(more 02 in water)

Amoeba _ J., /""-...,cell,>< / ~ /

/ '~ '-.-\. (less O2in cell) 02 "',\ used up in \

(' respiration r----/,,\ore C02 in C:lIl"-,\

. \ "'----0\...-..'1-----.J

Diffusion out of cell(less CO2 in water

around the cell)

Fig. 1.16Diffusion of oxygen and carbon

dioxide across the plasmamembrane of Amoeba

The Fundamental Unit of Life 15."

lpu,ewale,(solvent)

Water moleculesI-t---+--entering into

funnel

Semipermeablemembrane

Fig, 1.17 Asimple osmometer.Water molecules (solvent) entering the

sugar solution (solute)Semipermeability of the membrane prevents

sugar molecules moving into the solvent

----------------------

2. When the relative concentration of water and solutes on either sideof the plasma membrane are the same then there will be no netmovement of water across the plasma membrane. Such a solutionis known as an isotonic solution.

In such a solution, water crosses the cell membrane in bothdirections, but the amount going in is the same as the amountgoing out, therefore, there is no overall movement of water. In thissolution, the cell will stay the same siz€.

3. If the medium has a less concentration of water and higherconcentration of salt than the cell, it means that it is a veryconcentrated solution. The cell will lose water by osmosis. Such asolution is known as a hypertonic solution.

In such case, water crosses the cell membrane in both directions,but this time more water leaves the cell than it enters. Therefore,the cell will shrink. Thus, osmosis is a special case of diffusionthrough a selectively permeable membrane.

Let us tryout the following activity:

activity 5• Take an hen's egg.• Remove the egg shell by dissolving it in dilute hydrochloric acid. The hard shell of the egg

that is made ofmainly calcium carbonate gets dissolved. The egg is now enclosed by a thinouter semipermeable shell membrane.

• Put the egg in pure water for 5 minutes and then observe.

• What do you observe?• 10u will observe that the eggswells because waterenters the egg by osmosis through cell membrane.• Put a similar deshelled egg into concentrated salt solution for 5 minutes and observe it.

• What do you observe?

You will observe that the egg shrinks after a few minutes.

Why does the egg shrink? This is because the water passes out of the egg intothe salt solution as the salt solution is more concentrated.

You can also try a similar activity with dried raisins or apricots.

Soilparticle Thin film

of waterFig. 1.18 Absorption ofsoil waters by root hair

8ctivity&Demonstration of Osmosis in Raisins

• Put dried raisins and apricots in pure clean water.

• Leave them for some time and observe.• After some time you will observe that the raisins swell up due to endosmosis.

Now, place the swollen raisins into a concentrated salt solution and observe it.You will observe that the raisins shrink as they lose water due to exosmosis.

Some Examples of Osmosis

Unicellular freshwater organisms and most plant cells tend to gain waterthrough osmosis. Absorption of water by plant roots is also an example of osmosis.Hence, diffusion is important in exchange of gases and water in the life of a cell.In addition to this, the cell also obtains nutrition from its environment. Differentmolecules move in and out of the cell through a type of transport requiring use ofenergy.


: : Invaginatedmembrane

o :::J:::=- Solutes~Extracellular fluid

"1 ! Pinocytoticvesicle

Fig. 1.19 Diagrammatic representation of(A) The process of Pinocytosis and

(B) Phagocytosis through plasma membrane

o 00 0

~Ph,g",om,

~

A~\ Pseudopodium;:::::Y~~ Particulate material

Plasma membrane

Endocytosis

The flexibility of the plasma membrane also enables the cell toengulf food and other materials from its external environment. Suchprocesses are known as endocytosis. It is the active cellular intake ofmaterials. It is of two types:

(i) Phagocytosis (cell eating)

(ii) Pinocytosis (cell drinking)

(i) Phagocytosis: The transport ofsolid matter like food, phathogensand foreign matter across the membrane by forming detachablevesicles is called phagocytosis or cell eating. It is a common methodof feeding among the protozoans such as Amoeba and lowermetazoa (e.g., sponges) for engulfing food particles.

In amoeba and other protozoans, the food particles getsurrounded by an area of plasma membrane (cell surface)which forms an invagination along with the food organism. Theinvagination pinches off into a vesicle. Such vesicles with foodparticles are known as phagosomes.

(ii) Pinocytosis (cell drinking): The intake of droplets ofextracellular fluid along with sub-microscopic particles is calledpinocytosis or cell drinking.

Pinocytosis help in the intake of solutes such as insulin andlipoproteins in concentrated form. In this process extracellularfluid adheres to specific receptors of the membrane andinvagination is formed. This is drawn inwards and pinched offas a membrane-bound vesicle, the pinosome, containing thesolute. The pinocytic vesicle moves into the cytoplasm and itscontents are assimilated. Pinocytosis is a common occurrencein the cells lining the blood capillaries. Ions, sugar and aminoacids enter the cells by pinocytosis.

Exocytosis

The process of exudating the secretory materials from the cell is calledexocytosis or cell vomitting. Exocytosis occurs in various cells to remove undigestedresidues of substances brought in by endocytosis. In the gland cells, secretioncollects in a membrane-bound vacuole which now moves to the surface. Here itfuses with the plasma membrane. In the fused membrane, a channel is formed andthe contents of the vacuole are discharged outside the cell.

Table 1.2 Living and Non-living Parts of Cell

S.No. Living parts Non-living parts

1. Plasma membrane Cell wall (in plants)

2. Cytoplasm Vacuoles

(i) ER (smooth and rough)

(ii) Mitochondria

(iii) Colgi bodies

(iv) Ribosomes

(v) Lysosomes

(vi) Plastids (only in plants)

(vii) Centrioles (only in animals)


Cell Wall

Plant cells, in addition to plasma membrane, have another rigid outer coveringcalled the cell wall which lies outside the plasma membrane. The cell wall is nonliving and freely permeable and is secreted by the cell itself for the protection ofits plasma membrane. It is also present in bacteria, fungi and algae. It is absent inanimal cells. Cell wall determines the shape of a plant cell and prevents desiccationof cells.

The cell wall in bacteria is composed ofprotein and non-cellulosic carbohydrates,and in plants, of cellulose.

Functions

(i) It provides mechanical strength to the cell.

(ii) It controls the size and shape of the cells.

(iii) It counteracts, i.e., protects the cells against the osmotic pressure excreted bythe cell contents.

(iv) It helps in the translocation of water and other substances through xylemvessels and tracheids.

(v) It plays an important role in cell expansion.

(vi) Cutin and suberin prevent loss of water by evaporation.

(vii) Protects the cell from pathogens.

Plasmolysis

If plant cells are immersed in a hypertonic solution, water will diffuse out ofthe cell because concentration of water molecules in the cells is more than that inthe outer solution. Due to continuous exosmosis, protoplasm shrinks and separatesfrom the cell wall. This phenomenon is called plasmolysis.

To better understand this phenomenon let us perform the following activity:

activity 7• Mount the peel of a Rheo leaf and place it in a clean glass slide.

• Put a drop of strong solution of sugar or' salt on the mounted leaf on the slide and coverit with a coverslip.

• After few minutes observe it under the microscope.

• What do you see?• 10u will observe that the cell membrane shrinks after a few minutes. (See Fig. 1.20). These

changes can be explained by the fact that outer medium is hypertonic. Therefore, watermoves out of the leaf cells to cause plasmolysis.

18

Vacuole

Cytoplasm

Tonoplast--.......,,-

Normal cell Plasmolysis begins

Fig. 1.20 Structure of a pant cell

Space filledwith external

solution

Permanent plasmolysis


• Now take another peel of a Rheo leaf which has been placed in boiling water for a fewminutes.

• Prepare the slide similarly and observe it under the microscope.• Put a drop of strong solution ofsugar or salt on the slide.• Wait for a few minutes and observe it again.• What do you find? Did plasmolysis occur now?

You will observe that plasmolysis does not occur. This means that the processof osmosis does not occur in boiled plant cells. Due to boiling, i.e., high temperature,the cell membranes get damaged, hence, there will not be any osmotic activity.

This activity proves that the property of selective permeability exists only inthe living cell membrane and they are therefore, able to absorb water by osmosis.

activity 8Observation of Nucleus in the Animal Cells.

• Take a clean microscope slide and put a drop of water on it.• The teacher will provide you cotton bud from a freshly opened pack.• Gently wipe the lining ofyour cheek with one end of the cotton bud.• Smear the cotton bud over the centre of the slide.• Dispose offthe cotton bud immediately into a beaker ofdisinfectant provided by your teacher.

Cc;/ q I: ?

=-Fig. '.2'

• Put a drop of methylene blue stain on top of the smear.• Place a cover-slip on top and look for cells under a high powered microscope.

o

Cellmembrane

/Nucleus

60,

o \Cytoplasm

Fig. 1.22 Cheek cell of humans

What do you observe under the microscope?

Can you draw the structure that you are able to see on your observation sheet?

You will see a spherical or oval, dot-like structure near the centre of each cheekcell. These structures are called nucleus. You can draw diagrams of these cells andlabel them. Similar structure (nucleus) has been observed in the onion peel cells.

I (B) Nucleus

It is the most essential part of the cell which directs and controls all the cellularactivities. It is compared to the control room of a factory. It was first discovered byRobert Brown (1831).

The nucleus is usually dense, spherical or oval in shape. It occupies acentral position in the cell but it may be shifted to one side by vacuole as inplant cells.

Nucleus is bounded by two membranes, both forming nuclear envelope.Nuclear envelope encloses a space between two nuclear membranes and isconnected to a system of membranes called the Endoplasmic Reticulum(ER). The presence of nuclear envelope, separates the nuclear material from


rl:nlU

• A chromosome hastwo chromatidsattached to acentromere.

• Gene is formed ofDNA.

Chromatids ChromatidsFig. 1.24

Structure of chromosomes

the cytoplasm. Each nuclear membrane is about 90A thick and has a membranestructure similar to that of plasma membrane.

The nuclear envelope is perforated at intervals by the nuclear pores. Thenuclear envelope encloses the nuclear sap or nucleoplasm. Nuclear pores allowexchange of chemical substances between the cytoplasm and the nucleoplasm.Within nucleoplasm are present nucleolus and chromatin material.

~llcleolus may be one or more in number and are generally spherical. Theyare very large in cells that are active in protein synthesis. Their role is to synthesizeand to assemble RNA (ribonucleic acid) molecules and numerous proteins that makeup the ribosome. RNA is helpful in protein synthesis in the cytoplasm.

Chromatin material is a thin thread-like structure which is composed of DNA(Deoxyribonucleic acid) and proteins (i.e., histones). During cell division, chromatinthreads condense to form rod-shaped chromosomes. Each chromosome has twosimilar chromatids attached to a centromere. Chromatin material contains mostlyDNA (deoxyribonucleic acid). It plays an important role in heredity, i.e., transmitshereditary information from one generation to the next. The quantity of DNAvaries greatly in cells of different kinds of organisms. DNA stores all the informationnecessary for cell metabolism.

Chromosomes: Structure and Number

Chromosomes (Gr., chromo, coloured + soma, body) are thread-like darkstained bodies in the nucleoplasm of nucleus and discovered by W. Waldeyer in1888. Chromosomes are messengers of heredity. Chromosomes are thread-like, thin,coiled, elastic contractile structures, known as chromatin threads. This condition ofchromosomes is found in the interphase or resting stage ofthe cell. In the chromosomalmatrix are found embedded two similar spirally coiled threads, called chromonemata(singular, chromonema). Each chromosome contains two symmetrical chromatids.Each chromatid contains a single D A molecule. The chromatids are attached to eachother only by the centromere. Chromonema bears genes.

Genes

These are the functional units of DNA and are arranged in a single linear orderalong the DNA molecule. One gene controls one or more than one cell functions.Sometimes a single function is carried out by a set of genes.

The chromosome number is constant for all species and is given in thefollowing table:

Table 1.3 Chromosome Number in Some Organisms

Organisms Chromosome number in each body cell

Plants:Sunflower 34Garden pea 14

Onion 16

Maize 20

Rice 24

Animals:

Round worm (megalocephala) 2

Round worm (A. lumbricoides) 24


---------- -- -- ==~--~-------------------"'"

Silkworm

I28

Fruitfly 4

Housefly I 12

Mosquito I 6

Butterfly I 446

Cockroach I 24

Golden fish

I100

Frog 26I

Toad

I22

Rat 42

Rabbit 44

Monkey 42

Human beings I 46

Functions of Nucleus:

(i) Nucleus controls all the metabolic activities of the cell. Ifthe nucleus is removedfrom a cell, the protoplasm will ultimately dry up and die.

(ii) Nucleus regulates the cell cycle (division of cells).

(iii) It is related to the transmission of hereditary characters from parents tooffsprings.

I (C) Cytoplasm

When you observe the temporary mounts of onion peel and human cheekcells, you can see a large region of each cell enclosed by the cell membrane. Thisregion takes up very little ·strain. It is called cytoplasm. The cytoplasm is the quasifluid, jelly-like mass of protoplasm excluding the nucleus and surrounded by plasmamembrane. It is formed of proteins, nucleic acids, carbohydrates, lipids and certaininorganic substances.

Many small organelles are found inside the cytoplasm. These are known ascytoplasmic organelles. Each of these organelles performs a specific function for thecell.

FORMATIVE ASSESSMENTFA 1.6 Multiple Choice Questions

Select the right choice:

1. Chromosomes are made up of(a) DNA and protein (b) RNA and protein

(c) DNA and RNA (d) protein

2. Gaseous exchange in cells takes place by(a) osmosis (b) exocytosis

(c) diffusion (d) endocytosis


3. Amoeba acquires its food through a process known as

(a) plasmolysis (b) endocytosis

(c) exocytosis (d) both exocytosis and endocytosis

4. The process of plasmolysis in plant cell may be defined as

(a) breakdown/bursting of plasma membrane in a hypotonic medium.

(b) shrinkage of cytoplasm in hypertonic medium.

(c) shrinkage of cytoplasm in hypotonic medium.

(d) breakdown/bursting of plasma membrane in a hypertonic medium.

5. A cell may swell and even burst if(a) the concentration of water molecules within the cell is higher than the

concentration of water molecules in the surrounding medium.

(b) the concentration ofwater molecules in the surrounding medium is higherthan the concentration of water molecules within the cell.

(c) the concentration of water molecules is same in the cell and in thesurrounding medium.

(d) it is a plant cell and surrounded by a hypotonic solution.

FA 1.7: True or False

State whether the following statements are True or False.

1. In plant cells, a cell wall composed mainly of cellulose is located outside the cellmembrane.

2. There is shrinkage of the cell content away from the cell wall, when a livingplant cell loses water. This phenomenon is known as plasmolysis.

3. The cell will lose water by osmosis, if the surrounding medium has a higherconcentration of water than the cell.

4. A chromosome has two chromatids attached to a centromere.

5. Nucleus is responsible for transmission of heredi.tary characters from parentsto offsprings.

FA 1.8: Concept-based Worksheet

What will happen to an animal cell or a plant cell when placed in a sugar or saltsolution. One of the following three things could happen.

1. When the medium surrounding the cell has a higher water concentration thanthe cell, the cell will---'-- _

2. When the relative concentration of water and solutes on either side of theplasma membrane is the same then _

3. If the medium has a less concentration of water and higher concentration ofsalt then the cell will -----------------------

FA 1.9: If I

22

Pretend yourself to be an animal cell and answer the following questionsaccordingly.

1. List out your characteristic features with an example.

2. Write down the name of your cell organelles.

3. Distinguish between a plant cell and your cell.

\\'Ie tunQamenta\ Unit G1 Li1e

~ ~'~Y"~'.1~t~jii~~tI£-FA 1.10: Activity-based Questions

Prepare an experimental set-up consisting of two beakers. One beaker has waterto which peeled pieces of carrot have been added. In the second beaker, saturatedsugar/salt solution has been put in which peeled pieces of carrot have been added.Preaper this set-up and keep it for 6-8 hours or overnight before taking it to theclass.

Show the experimental set-up to the students explaining the content of eachbeaker and time duration for which carrots were immersed in the solution.

Ask the students to observe the carrots in the two beakers and compare the physicalstate of the carrots carefully.

Answer the questions given in the worksheet.

1. What is the difference in the physical state of the carrots as observed in the twobeakers? .

2. Name the process involved that has caused a change in the carrot piece in onebeaker.

3. Why has the above process occurred?

4. Name the type of solution in beaker A and B with respect to the carrot pieces?

5. Name one process in your daily life which works on the same principle.

Cell Organelles

The cytoplasm of a cell contains a variety of organelles having tJ;leirpermanent structures with definite functions. These are membrane-bound, such asmitochondria, lysosomes and peroxisomes.

Cell organelles are the living parts of the cell found embedded in the cytoplasm.These are smaller in size and bounded by unit membrane like plasma membraneand thus, keeps its own contents separate from the external environment. Large andcomplex cells, including cells from multicellular organism, need a lot of chemicalactivities to support their complicated structure and function. To keep these activitiesof different kinds separate from each other, cells have developed membrane boundorganelles within themselves. They form the living part of the cell and each of themhas a definite shape, structure and function. Some of these organelles are visibleonly under an electron microscope. The important cell organelles are describedbelow.

I 1. Plastids

Plastids are the largest cytoplasmic organelles bounded by a doublemembrane. These are found in most of the plant cells and in some photosyntheticprotists. These are absent in prokaryotes and animal cells. Like the mitochondriaplastids also have their own genetic material and protein synthesising machinery,(i.e., DNA, RNA) and ribosomes. They are self-replicating organelles like themitochondria, i.e., they have the power to divide. These are of following threetypes:

(a) Chromoplasts: Coloured plastids(b) Chloroplast (Green coloured plastids): They contain chlorophyll pigment.

(c) Leucoplasts: Colourless plastids.


Chloroplasts

Nature and Occurrence

Circular-~~~'--

DNA

(or matrix)

The plastids with green pigment, thechlorophyll, are called chloroplasts. These arepresent in green algae and higher plants. Thepresence ofchlorophyll makes them ofutmostbiological importance. The chlorophyllenables the chloroplasts to harness kinetic solarenergy and trap in the food substances in theform of potential energy. All living organismsdirectly or indirectly depend on them forobtaining energy. Therefore, chloroplasts arethe 'kitchens of the cells'. Each chloroplast isbounded by two membranes. It shows twodistinct regions.

(a) Stroma: It is the colourless proteinaceous ground substance that fills thechloroplast. It contains a variety of photosynthetic enzymes, starch grains,DNA and ribosomes. It is the site of dark reaction during photosynthesis.

(b) Grana: These are stacks of membrane-bounded, flattened, discoid sacscontaining chlorophyll molecules. These are the main functional units ofchloroplasts. It is the site of light reaction during photosynthesis.

Functions

. Photosynthesis is one of the most fundamental biological functions. By meansofchlorophyll contained in chloroplasts, the green plants trap the energy of sunlightand transform it into chemical energy. This energy is stored in the chemical bondsproduced during the synthesis of various food stuffs, like starch, etc.

Chromoplasts give colours to flowers and fruits which attract insects forpollination.

Leucoplasts are involved in the synthesis and storage of various kinds of foodin the form of starch, oils and proteins.

I 2. Mitochondria

Under electron microscope, a mitochondrion appears asa double walled structure like an ice box of thermos bottle. Itconsists of an outer and inner membrane and enclosed withinthem are two compartments or chambers. The outer membraneis very porous. Inner membrane is folded into the matrix as anincomplete septa, called cristae (singular crista). These increasethe surface area of the inner membrane and divide the innerchamber. The inner membrane (or M.face) is studded (dotted)with numerous spherical or knob-like elementary particles or

The mitochondria (Gr. rnito = thread; chondrion = granule) are tiny structuresof variable shapes; cylindrical, spherical, or rod-shaped andthe average size of mitochondria is 0.2 ,urn to 2 ,urn, distributedin the cytoplasm. These convert the potential energy of foodstuff into kinetic energy and hence are commonly knownas the 'power house' of cell. These are essential for aerobicrespiration.

Ultra Structure

Outer membrane

---Outer chamber

='!~---Matrix

...---- Inner membrane

"ajliU~;,;~~t---F1 particle

::=::L~~==~--- Cristae

~~Dj~ =.,------- DNA molecule

Fig. 1.26 Internal structure of Mitochondria

...,,----- Ribosome


oxysomes. The inner cavity of mitochondria are filled with a homogeneous, gel-like(proteinaceous) matrix which contain a few small sized ribosomes, a circular DNAmolecule and phosphate granules. Therefore, mitochondria are able to make sureof their own proteins. Mitochondria are absent in bacteria and red blood cells ofmammals.

Functions

Mitochondria are the respiratory organs of the cells. The carbohydrates andfats present in the cells are completely oxidized into CO2 and H 20 with the help ofenzymes present in the mitochondria. During oxidation, a large amount of energyis released which is used by the mitochondria for the synthesis of the energy richcompound, the adenosine triphosphate (ATP). Since they synthesize ATp, they arealso known as power houses of the cell. This energy is used by the cell for performingvarious chemical activities.

I 3. Vacuoles

Vacuoles are sap-filled vesicles in the cytoplasm. These are found in all theeukaryotic cells. They are the kinds of storage sacs. In animals, a number of smallsize and temporary vacuoles are found which store water, glycogen and proteins. Itsmembrane is typically a single unit membrane and is associated with the maintenanceofwater balance (osmoregulatory organ in protozoans) or ingestion offood substance(food vacuole). Thus, in unicellular organisms such as amoeba and paramecium, thefood vacuole contains the food items that the animal has consumed.

A plant cell has a single large vacuole which is permanent. In plant cells, thevacuole increases in size as the cell enlarges. The central vacuole of some plant cellsmay occupy 50-90 per cent of the cell volume. Due to the central position of thevacuole, the nucleus and other cell organelles are pushed near the boundary wall.In plants, the vacuoles are bounded by a single unit membrane called tonoplast.These are filled with a fluid, the cell sap. The cell sap is rich in minerals, sugars,amino acids, esters, water soluble proteins and waste products in solution or in theform of crystalline deposits.

Functions

(i) Cell sap of vacuoles maintains the turgidity of plant cells.

(ii) This supports the green parts of the plant.

(iii) Vacuoles playa key role .in growth by elongation of cells.

(iv) Vacuoles store water, minerals, and reserve food in the form of sugar.

I 4. Endoplasmic Reticulum (ER)

It is a network of fluid-filled interconnecting membranous tube like structurescovering the most part of the cytoplasmic matrix. It occurs in three forms, cisternae(closed fluid-filled gas), vertical and tubules. The E.R. membrane is similar instructure to the plasma membrane. It communicates with the plasma membraneand also with the nuclear envelope.

Endoplasmic reticulum is of two types:

(a) Rough endoplasmic reticulum (RER): With its outer surface are attachedribosomes which synthesize proteins. It is well developed in protein synthesizingcells, like pancreatic and liver cells.

(b) Smooth endoplasmic reticulum (SER): It is continuous with rough ER. Itssurface is smooth, devoid of ribosomes. It is found in glycogen rich regions.These secrete lipids.

Fig. 1.27

~~~-~~.~~~<>-~~<>-.

I:"o~-o-<>o-~~ o-o

~::.~

Fig. 1.28Endoplasmic reticulum (Rough)


-------- ------~-------

25

Fig. 1.29Endoplasmic reticulum (Smooth)

• Golgi bodies aresecretory organelles.It secretes enzymes,mucous, pigments,etc.

Golgi [network _

Secretoryvesicle

Functions

The main functions of ER are as follows:

(i) ER forms a network in cytoplasmic matrix, giving mechanical support to thecell.

(ii) It functions as an intracellular transport system for various substances. ERcollects synthetic products of cell and then transports them outside the cell. Italso transports the RNA and nucleoproteins from the nucleus to the cytoplasmwhere protein synthesis occurs.

(iii) Protein synthesis occurs on the surface of rough ER by ribosomes. Theseproteins are either used within the cell or exported outside the cell.

(iv) Synthesis of lipids in collaboration with Golgi complex occurs on the surfaceof smooth ER. Synthesis oflipoproteins and glycogen occurs on smooth ER inliver cells.

(v) Smooth ER membrane contains enzymes for lipid synthesis and for lipidsoluble drugs and other harmful compounds. These enzymes detoxify theabove drugs and make them water soluble so that they may be excreted inunne.

15. Goigi Apparatus (Golgi Complex)

Golgi apparatus was discovered by Camillo Goigi in 1898 in the cytoplasm ofnerve cells. Morphologically, it is very similar in plant and animal cells. It consists ofstacks offlattened disc-shaped bags or cisternae, and associated discharged secretoryvesicles. It is a single large structure located in between the nucleus and pole of thecell in which secretion takes place, such as in thyroid cells, exocrine pancreatic cellsand mucous cells of intestinal epithelium. In plant cells they are called 'dictyosomes'.

Under electron microscope, GolgiDischarge I b fl d

vesicle comp ex are mem ranous attene sacs(cisternae), tubules and vesicles and largevacuoles. Flattened sacs occur from 3 to 7arranged in parallel rows, one above theother. Each stack of cisternae has a proximalforming a convex face closer to the nuclearenvelope or ER and a distal or maturingconcave face that encloses large secretoryvesicles. Small transition vesicles or tubulesare present upon Golgi cisternae. A largenumber of small vesicles which are associated

Fig. 1.30 Goigi apparatus with each Golgi stack transport proteins andlipids both to and from the Golgi apparatus.

Golgi complex is not found in bacteria, blue-green algae, sperms and redblood cells of mammals and other animals.

The Golgi apparatus originates from smooth endoplasmic reticulum which inturn has originated from rough ER and finally becomes the Golgi cisternae.

Functions

(i) Golgi complex is the secretory organelle of the cell and transports thesubstances (pancreatic enzymes, mucous secretions, secretion of mammaryglands, thyroxin, pigments, etc., outside the cell) as well as intracellularly(within the cell). For export, secretion is packaged into vesicles, which aredetached and form flattened sacs transported across the cell membrane.


Camillo Golgi

(ii) During cell division, Golgi complex forms the cell plate.

(iii) Synthesis of cell wall, plasma membrane, and peroxisomes occur from Golgiapparatus.

(iv) Acrosome of sperm is formed by the Golgi apparatus.

Camillo Golgi

Camillo Golgi was born in 1843 at Cartano near Brescia. Hestudied medicine in the University of Pavia. He graduated inmedicine in 1865 and worked in the Hospital of St. Matleoin Pavio. In 1872 he became the Chief Medical officer in ahospital at Abbiate Grasso. He worked on nervous system

in a little kitchen of the hospital turned into a laboratory.He developed a method of staining individually nerve andcell structures, which was called as black reaction. He usedweak solution of silver nitrate to trace the ramificationsof nerve cells. Throughout his life he continued to workon these lines, modifying and improving this technique. In recognition of hiswork, he got some highest honours and awards. He, along with Santiago Ramony

Cajal, got the Nobel Prize in 1906 for their work on the structure of nervous system.

I 6. Ribosomes

In prokaryotic cells, ribosomes are always found free, but ineukaryotic cells, these are found either free in or attached on the roughER. Ribosomes are also found in mitochondria and chloroplasts ofeukaryotic cells. These are dense and rounded granules visible onlyunder electron microscope. Ribosomes contain RNA and proteins.Lipids are not found in ribosomes.

Function

Ribosomes are the sites where proteins are synthesized.

Endoplasmicmembrane

Ribosome

I 7. Lysosomes Fig. 1.31 Protein synthesis on the ribosome of RER

Lysosomes are tiny spherical sac-like structures of cyroplasm. Each lysosomehaving a single limiting unit membrane contains powerful hydrolytic enzymes.These enzymes are capable of digesting all organic materials. These enzymes aresynthesized in the RER which are brought to the golgi complex. Lysosomes areformed by the Golgi complex.

Functions

(i) Lysosomes are involved in digestion of microorganisms like bacteria, etc.,entering the cell by phagocytosis.

(ii) Lysosome can digest the organic substances of the same cell in which it belongs.This process is called autolysis. Hence, lysosomes are called digestive bags.

(iii) The dead or damaged cells are also digested by the enzymes released from thelysosomes of the same cells. Hence, these are called suicidal bags.

(iv) For digestion in the cell, the material to be digested is surrounded by amembrane forming an endosome. It fuses with the lysosome, enzymes ofwhich digest the contents of endosome.

(v) Lysosomes initiate cell division.

• Lysosome containsdigestive enzymes,for the digestion offoreign material andtheir own damagedcell.


• Oxidative reactionsoccur in peroxisomeswith the help ofoxidative enzymes.

Fig. 1.32 Centriole

I 8. Peroxisomes

Peroxisomes are ovoid granules surrounded by a single membrane. Theyare found in abundance in liver and kidney cells. They contain certain oxidativeenzymes and carry out some oxidation reactions.

Functions

(i) They help in the removal of toxic substances.

(ii) They help in lipid metabolism and convert fat into carbohydrates.

I 9. Centrosome

The term centrosome was given by T. Bo\'eri in 1888, meaning central body.It is found only in animal cells and is generally absent in cells of plants. Eachcentrosome contains two rod-shaped granular structures called centrioles: It is notbounded by any membrane and are made up of microtubules. In plant cells, polarcaps are present which function as centrioles.

Functions

(i) From the centrosome spindle fibres r~diate as an aster in animal cells andlower plants. At the time of cell division, centrioles separate and migrate toopposite poles of the cell and then spindle is formed in between them, whichhelp in cell division.

(ii) In plant cells, polar caps are involved in the formation of spindle.

Each cell, thus acquires its structure and ability to function because of theorganization of its membrane and organelles in specific ways. As a result, each typeof cell got a basic structural organization. This helps the cell to perform functionslike respiration, obtaining nutrition and cleaning of waste material, or formingnerve proteins. Thus, the cell is the fundamental structural functional unit of life.This conclusion forms the essence of the cell theory.

Table 1.4 Differences between Animal and Plant Cell

S.No. Features I Animal Cell Plant Cell

l. Size Generally small Larger thap animal cell

2. Cell wall Absent Present

3. Plastids Absent Present

4. Vacuoles Small, many and temporary Permanent and large, filled withcell sap occupying the centre ofthe cell.

5. Golgi apparatus Present near nucleus Present and called dictyosome.

6. Centrioles IPresent within centrosome Absent. Polar caps are present.

FORMATIVE ASSESSMENTFA 1.11: Multip e Choice Questions

Select the right choice

1. Which one of the following is called the 'digestive bag or suicidal bag'?

(a) Centromere (b) Lysosome

(c) Nucleus (d) Mitochondria


2. Which one of the following is not a function of vacuole?

(a) Storage

(b) Providing turgidity and rigidity to the cell

(c) Locomotion

(d) Waste excretion

3. The cell organelle involved in forming complex sugars from simple sugars are

(a) endoplasmic reticulum (b) ribosomes

(c) plastids (d) golgi apparatus

4. The power house of a cell is

(a) chloroplast (b) nucleus

(c) mitochondria (d) golgi apparatus

5. Which of the following statement is not related to endoplasmic reticulum?(a) It acts as a channel for the transport of materials between various regions

of the cytoplasm.

(b) It functions as a cytoplasmic framework providing a surface for some ofthe biochemical activities of the cell.

(c) Ribosomes are the sites of protein manufacture.

(d) It can be the site of energy generation.

FA 1.12: Complete the Data

Complete the data given in the following table.

Features I Animal cell Plant cellI

Cell wall Present

Plastids

Vacuoles Small, many and temporary Permanent, filled withoccupymg of the cell.

Goigi apparatus Present near Present and called

Centrioles Present within Absent and are present.

FA 1.13: Diagram-based Worksheet

Give below are the figures representing plant and animal cells. Label any fiveorganelles common in both plant and animal cells.

Tile Fundamental Unit of Life 29

FA 1.14: Mapping Type Worksheet

SUMMARY

30

I Cell was first observed by Robert Hooke in apiece of cork in 1665. Anton von Leeuwenhoekdiscovered free bacteria and red blood cells and observed their inner organisation.

I Cell theory: Cell is a mass of protoplasm limited in space by a cell membrane andpossessing a nucleus. Cell is the unit of life. Cell theory was discovered by Schleidenand Schwann. Cells originate from the pre-existing cell.

I Cell shape may be fixed like Paramecium or variable like Amoeba. A cell is bound byselectively permeable membrane, the plasma membrane and contains a nucleus andcytoplasm. Nucleus is also bounded by a nuclear membrane enclosing nucleoplasm.Cell membrane is selectively permeable allowing ions to move in and out. It iscomposed of double layers of lipids and proteins.

I In plants, cell wall lies outside the plasma membrane. It is composed of cellulose. Cellwall is lacking in animal cells. Cytoplasm contains a number of cellular organelles,such as nucleus, endoplasmic reticulum, ribosomes, Golgi complex, Iysosomes,peroxisomes, mitochondria, plastids, and centrosome.

I Nucleus is found in all cells and is bound by nuclear envelope (perforated) and enclosesnuclear sap. Nucleus contains nucleolus and chromatin material (chromosomes).

I Endoplasmic reticulum is a branching tubular system found in cytoplasm andconnected with nuclear envelope and plasma membrane. It functions as an intracellular transport system and synthesis of proteins on the RER.

I Ribosomes are the sites where protein synthesis occurs.

I Golgi apparatus originate from ER and contain various cellular secretions. Golgiapparatus in plant cells is called dictyosome.

I Lysosomes develop from Golgi apparatus and contain digestive enzymes.

I Mitochondria are the sites for cellular respiration. ATP is produced in them and hence is calledthe powerhouse of cells. Mitochondria are not found in prokaryotic cells and red blood cells.

I Plastids are found in plant cells. Chloroplasts, a type of plastid, help in photosynthesis.I Plastids are of three types-chloroplasts (green), chromoplasts (coloured-other

than green) and leucoplasts. Chloroplasts help in the photosynthesis. A chloroplastis formed of a number of grana. A granum is formed of a number of flattened discsarranged in a pile to form thylakoids. Thylakoids possess chlorophyll.

I Centrosomes are found only in animal cells. They initiate and regulate the chromosomalmovement.

I Vacuoles are fluid-filled membrane bound structures, found in plant cells. Onlyprotozoans (animals) possess temporary vacuoles. Vacuoles help in maintaining theosmotic pressure of cells.


FORMATIVE ASSESSMENT FOR PRACTICEFA 1. Wordplay

Write the wordplay using the word below.

Awordplay is one where you choose a word or name and use each letter in the name as the beginningof a word or line that says something about that person or topic.

Example: Awordplay using the word "SUN".

Sometimes when we go to the beach, we get sunburnt.

Usually, if I put sunblock on my skin, Ido not get burnt.

Noon is when I'm really prone to burn.

p-----------------------------L _

A _

S _

T .,.--- _

1 _

D _

S _

FA 2. Young Scientist

To prepare a temporary mount of onion peel

You will need: Onion bulb, forceps, watch-glass with water, a glass slide, dropper, coverslip,safranine solution, microscope, etc.

o Take a small piece of onion bulb.

o Peel off the skin from the concave side of the onion with the help ofa pair offorceps.

o Put the skin immediately in a watch-glass containing water to prevent it from getting folded or dry.

"'-I

o Transfer the peel from watch-glass onto the glass slide.

o Now, put a drop ofsafranine solution on this piece using a dropp,,/ollowed by coverslip.

o Place the slide on the microscope stage for obseroation.

Results:

o You will obsen}e that the peel consists of _

The Fundamental Unit of Life 31 _

FA 3. Flow-chart Based Worksheet

Instructions: Given below is an incomplete flow-chart on cell organelles.

• Some boxes/spaces in the flow-chart have been left blank.

• Complete the flow-chan adding terms/names/functions as and where required.

Cell Organelles

EndoplasmicReticulum

Mitochondria Plastids

Hasribosomesattached tomembranes

Noribosomesattached tomembranes

Packagingof products

ProduceAlP

Suicide bagsof the cell

Known as Have theirown

Not presentin

Storagesacs

for solid orliquid

contents

Produces Produces

FA 4. Word Box

Topic: Cell

Directions: Complete the paragraph given below choosing appropriate words from the word boxin the space provided.

eukaryotes

plasma membrane

Robert Hooke

present

absent

cork slice

selectively permeable

prokaryotes

Cells were first discovered by In 1665. He

observed the cells in a with the help ofa primitive

microscope. Organisms with cells in which the nuclear material is not bounded by a definite

nuclear membrane are called . While the advanced and complete cell in

which the nucleus has a definite nuclear membrane is called _

In a prokaryotic cell, most of the other cytoplasmic organelles are however they

are in eukaryotic cells.

The outermost covering of the cell that separates the contents of the cell from its external

environment is called It prevents and allows

entry and exit of only limited materials In and out of the cell. Therefore, it is called

__________________ membrane.


FA 5. Seminar

Topic: Nucleus

Directions: The students may divide themselves into a group of eight to ten for a collectiveresearch/study on the given topic. The topic can be divided into following sub-topicsfor presentation.

• Discovery of nucleus• StruclUre of nucleus• Chromatin material

FA 6. True or False


1. Most malUre plant cells have a large central vacuole that helps to maintain the lUrgidity of thecell and stores important substances including wastes.

2. Plastids are present only in plant cells and also have their own Dl\A and ribosomes.3. The smooth endoplasmic reticulum helps in the manufacture of fat molecules or lipids

important for cell function.

4. Lysosome contains digestive enzymes for the digestion of foreign material and their owndamaged cell.

5. Vacuoles are secretory organelles which secrete enzymes, mucous, pigments, etc.

6. Rough endoplasmic reticulum has smooth surface and is devoid of ribosomes.7. Mitochondria are said to be the powerhouse of the cell as ATP is generated in them.

FA 7. Concept-based Worksheet

The cytoplasm of a cell contains a variety of organelles having their permanent structures with definitefunction. These are membrane-bound, such as mitochondria, Iysosomes, peroxisomes, endoplasmicreticulum and vacuoles.

Instructions: On the basis of above information provided in the book answer the followingquestions.

1. Differentiate between rough and smooth endoplasmic reticulum. How is endoplasmicreticulum important for membrane biogenesis?

2. Describe the structure and function of Golgi apparalUs.

3. Why are lysosomes also known as 'scavengers of the cells'?

4. vVrite the site where ATP synthesis takes place in mitochondrion.

5. Define chromoplasts, chloroplasts and leucoplasts.

6. Write down the main functions of vacuoles.

FA 8. Multiple Choice Questions

Select the right choice.

1. Which of the following can be made into crystal?(a) A Bacterium (b) An Amoeba

(c) A Virus (eI) A Sperm


2. A cell will swell up if(a) The concentration ofwater molecules in the cell is higher than the concentration of water

molecules in surrounding tnediurn(b) The concentration of water molecules in surrounding medium is higher than water

molecules concentration in the cell

(e) The concentration of water molecules is same in the cell and in the surrounding medium

(d) Concentration of water molecules does not matter

3. Chromosomes are made up of

(a) DNA (b) protein(e) D A and protein (d) R A

4. Which of these options are not a function of Ribosomes?(i) It helps in manufacture of protein molecules

(ii) It helps in manufacture of enzymes

(iii) It helps in manufacture of hormones

(iv) It helps in manufacture of starch molecules

(a) (i) and (ii) (b) (ii) and (iii)

(e) (iii) and (iv) (d) (iv) and (i)

5. Which of these is not related to endoplasmic reticulum?

(a) It behaves as transport channel for proteins between nucleus and cytoplasm(b) It transports materials between various regions in cytoplasm

(e) It can be the site of energy generation(d) It can be the site for some biochemical activities of the cell

6. Following are a few definitions of osmosis

Read carefully and select the correct definition(a) Movement of water molecules fi'om a region of higher concentration to a region of lower

concentration through a semipermeable membrane.

(b) Movement of solvent molecules from its higher concentration to lower concentration

(e) Movement of solvent molecules fi'om higher concentration to lower concentration ofsolution through a permeable membrane.

(d) Movement of solute molecules from lower concentration to higher concentration ofsolution through a semipermeable membrane.

7. Plasmolysis in a plant cell is defined as(a) break down (lysis) of plasma membrane in hypotonic medium(b) shrinkage of cytoplasm in hypertonic medium

(e) shrinkage of nucleoplasm

(d) none of them

8. Which of the following are covered by a single membrane?(a) Mitochondira (b) Vacuole

(e) Lysosome (d) Plastid9. Find out the false sentences

(a) Golgi apparatus is involved with the formation oflysosomes

(b) Nucleus, mitochondria and plastic have DNA; hence they are able to make their ownstructural proteins.

(e) Mitochondria is said to be the power house of the cell as ATP is generated in them.(d) Cytoplasm is called as protoplasm

34 The Fundamental Unit of life

(b) 10-9ill

(d) 10-3 m

(b) Purkinje

(d) Robert Brown

(b) golgi apparatus

(d) nucleus

,.. ~.J,.,.10. The proteins and lipids, essential for building the cell membrane, are manufactured by

(a) rough endoplasmic reticulum (b) golgi apparatus(e) plasma membrane (d) mitochondria

11. The undefined nuclear region ofprokaryotes are also known as(a) nucleus (b) nucleolus

(e) nucleic acid (d) nucleoid

12. The cell organelle involved in fonning complex sugars from simple sugars are(a) endoplasmic reticulum (b) ribosomes

(e) plastids (d) golgi apparatus

13. Which out of the following is not a function of vacuole?(a) Storage (b) Providing turgidity and rigidity to the cell

(e) Waste excretion (d) Locomotion

14. Amoeba acquires its food through a process, termed(a) exocytose (b) endocytosis

(e) plasmolysis (d) exocytosis and endocytosis both

15. Cell wall of which one of these is not made up of cellulose?(a) Bacteria (b) H)'drilla

(e) Mango tree (d) Cactus

16. Silver nitrate solution is used to study

(a) endoplasmic reticulum (b) golgi apparatus

(e) nucleus (d) mitochondria

17. Organelle other than nucleus, containing DNA is

(a) endoplasmic reticulum (b) golgi apparatus

(e) mitochondria (d) lysosome

18. Kitchen of the cell is

(a) mitochondria (b) endoplasmic reticulum

(e) chloroplast (d) golgi apparatus

19. Cell arises from pre-existing cell was stated by

(a) Haeckel (b) Virchow

(e) Hooke (d) Schleiden

20. Cell theory was given by

(a) Schleiden and Schwann (b) Virchow

(e) Hooke (d) Haeckel

21. The only cell organelle seen in prokaryotic cell is

(a) mitochondria (b) ribosomes

(e) plastids (d) lysosomes

22. Organelle without a cell membrane is

(a) ribosome

(e) chloroplast

23. l!.tm is(6,) 10-6 m

(e) 10-10 m

24. Living cells were discovered by

(a) Robert Hooke

(01) Leeuwenhoek

The Fundamental Unit of Life 35 VK Biology IX

Answers

1. (e)

5. (e)

9. (a)

13. (d)

17. (e)

21.(b)

2. (b)

6. (a)

10. (a)

14. (b)

18. (e)

22. (a)

3. (e)

7. (b)

11. (d)

15. (a)

19. (b)

23. (a)

4. (e)

8. (b)

12. (d)

16. (b)

20. (a)

24. (e)

FA 9. Oral Assessment

Instructions: Give the answers carefully.

1. What is the function of the cell wallO

2. What will happen to a cell if its nucleus is removed?

3. Where are genes located?

4. What is plasmolysis?

5. Is the plant cell wall living or dead?

6. Do the plant cells contain centriole?

7. Which cell organelle is responsible for intracellular transport'

8. Which cell organelle is called the suicidal bag?

9. What are the main functions of vacuoles?

10. ""hat is the primary function of leucoplasts?

FA 10. Paper Pen Test1.'Answer the following questions.

(b) Do you agree that "A cell is a building unit of an organism"?

(e) Why does the skin of your figures shrink when you wash clothes for a long time?

(d) How are chromatin, chromatid and chromosomes related to each other?

(e) How is bactirial cell different from an onion peel celIOif) What are consequences ofthe following conditions?

(i) A cell containing higher water concentration than the surrounding medium.

(ii) A cell having low water concentration an compared to its surrounding medium.(iii) A cell having equal water concentration to its surrounding medium.

if) Name two organelles in the plant cell that contain their own genetic material andribosomes.

2. Fill in the Blanks.(a) Cell theory was proposed by and _

(b) serves as channels for the transport of materials between vanousregious of the cytoplasm or between the cytoplasm and the nucleus.

(e) are known as powerhouses of the cell.

(d) lack any membranes and hence do not show characteristics of eye untilthey enter a living body and use its cell machinery to multiply.

(e) is the packaging and despatching unit of the cell.

~--36 The Fundamental Unit of Life

... ..-

J1 .,'~ ,,~

3. Match the following.

Column I Column II

(a) Vacuoles (i) Suicidal bags of a cell

(b) Nucleoid (ii) Powerhouse of a cell

(c) Lysosomes (iii) Bacteria

(d) Mitochondria (iv) Storage sacs of a cell

(e) Food vacuole (v) "ucleus

I If) Chromatin material and nucleolus (vi) Amoeba

LysosomesVacuoles

golgi apparatusmitochondria

(ii)

(iv)

(ii)

(iv)

4. True or False.(a) Lysosomes keep the cells clean by digesting foreign materials and worn out cell organelle.(b) Osmosis plays an important role in gaseous exchange between the cells as well as the cell

and its external environment.

(c) Prokaryotic cells have no membrane-bound organelles, their chromosomes are composedof only nucleic acids and they have only very small ribosome as organelle.

(d) An undefined nuclear region containing only nucleic acids in eukaryotes is called anucleoid.

(e) Smooth endoplasmic reticulum detoxifies many poisons and drugs.

5. Multiple Choice Questions.(a) Lipid molecules in the cell are synthesised hy

(i) smooth endoplasmic reticulum

(ii) rough endoplasmic reticulum

(iii) golgi apparatus(iv) plastids

(a) Lysosomes arises from

(i) endoplasmic reticulum

(iii) nucleus

(a) Select the odd one out.

(i) The movement of water across a semipermeable membrane is affected by the amountof substances dissoh'ed in it.

(ii) Membrane are made of organic molecules like proteins and lipids.

(iii) Molecules soluble in organic solvents can easily pass through the membrane.

(iv) Plasma membranes contain chitin sugar in plants.

(a) Which cell organelle plays a crucial role in detoxifying many poisons and drugs in acell?

(i) Golgi apparatus(iii) Smooth endoplasmic reticulum

(a) Find out the correct sentence.

(i) Enzymes packed in lysosomes are made through RER.(ii) Rough endoplasmic reticulum and smooth endoplasmic reticulum produce lipid and

protein respectively.(iii) Endoplasmic reticulum is related to the destruction of plasma membrane.

(iv) Nucleoid is present inside the nucleoplasm of eukaryotic nucleus.

The Fundamental Unit of Life 37 II'J!IiiiiIi IIl"l I

SUMMATlVE ASSESSMENT

A. Textbook Questions1. Who discovered cells and how?

Ans. The cell was first discovered by Robert Hooke in 1665. He examined thin slices of cork undera self·made microscope and saw a multitude of tiny hollow spaces that he remarked lookedlike the walled compartments of a honeycomb. He termed these spaces as 'cell' meaning'small room' in Latin.

2. Why is the cell called the structural and functional unit of life?

Ans. All living organisms are made up of cells. This shows that the cell is the structural unit oflife.Each living cell has the capacity to perform certain basic functions that are characteristics ofall living forms. For example, phagocytic cells eat or kill unwanted or foreign particles insidethe body (e.g., WBCs) some cells, e.g., pancreatic cells, small intestine cells, liver cells secreteenzymes and hormones. That is why cell is called the structural and functional unit of life.

3. How do substance like CO2 and water move in and out of the cell? Discuss

Ans. Carbon dioxide and water move across a cell by the process of diffusion and osmosisrespectively. When the concentration of CO2 is low outside the cell as compared to inside, itmoves out, i.e., from a region of high concentration to a region oflow concentration.

Also, when concentration ofwater increases inside the cell as compared to its exterior, it movesacross the plasma region from a region of its high concentration to its low concentration.

4. Why is plasma membrane called a selectively permeable membrane?

Ans. Plasma membrane is called selectively permeable membrane because it allows the movementof only selected molecules across it.

5. Fill in the gaps in the following table illustrating differences between prokaryotic andeukaryotic cells.

Ans.

Prokaryotic cell

I. Size: generally small (1-10 /Lm)

I/Lm = 10-6 III

2. Nuclearregion: _

and known as _

3. Chromosome: single

4. Membrane-bound cell organelles absent.

Prokaryotic cell

I. Size: generally small (1-10 /Lm)

I /Lm = lO-6m

2. l\uclear region: Undefined due to theabsence of nuclear membrane and knownas nucleoid.

3. Chromosome: single

4. Membrane-bound cell organelles absent.

38

Eukaryotic cell

1. Size: generally large (5-100 /Lm)

2. Nuclear region: Well-defined and surrounded

by a nuclear membrane.

3. More than one chromosome.

4. _

Eukaryotic cell

I. Size: generally large (5-100 /Lm)

2. "Juclear regIon: Well-defined andsurrounded by a nuclear membrane.

3. More than one eh romosome.

4. \lembrane-bound cell organelles (e.g.,chloroplasts, Golgi bodies, etc.) present.

The Fundamental Unit of Lrte

-:h ..... ':.,'i>d.... ~ .~

6. Can you name the two organelles we have studied that contain their own genetic material?

Ans. Plastids and mitochondria.

7. If the organisation of a cell is destroyed due to some physical or chemical influence, whatwill happen?

Ans. Cell organelles are responsible for the organisation and proper functioning of a cell, as eachof them perform some specific functions. 'Iaturally, if any of these organelles are destroyed,the functions of the cell will be stopped and it may also result in the death of the celL

8. Why are lysosomes known as suicidal bags?

Ans. Lysosomes are known as 'suicidal bags' because when cell gets damaged during the disturbancein cellular metabolism, lysosomes may burst and the digestive enzymes thus released digestthei r own celL

9. Where are proteins synthesised inside the cell?

Ans. Ribosomes present in the cell synthesise proteins and are called protein factories of the celLThese may be attached on the surface of rough endoplasmic reticulum or lie freely in the celL

10. Make a comparison and write down ways in which plant cells are different from animalcells.

Ans. The differences between plant cells and animal cells are as follows:

Plant cells Animal cells

I. Plant cells are larger in size. I. Animal cells are comparatively smaller insize.

2. They contain cell wall made of cellulose. 2. Cell wall is absent. Only plasma membranewhich IS present outside the plasma is present.membrane.

3. They contain plastids. t.e., chloroplasts. 3. Plastids are absent.leucoplasts and chromoplasts.

4. Centrosome is absent. 4. Centrosome is present.

5. Larger vacuoles are present. 5. Vacuoles either absent or are very small inSize.

6. Food is stored in the form of starch. 6. Food is stored in the form of glycogen.

7. Lysosomes are either absent or are very few 7. More number of prominent Iysosomes arein number. present.

11. How is a prokaryotic cell different from a eukaryotic cell?

Ans. Differences between prokaryotic cell and eukaryotic cell are as under:

Prokaryotic cell Eukaryotic cell

L Prokaryotic cells are generally small in size. L Eukaryotic cells are comparatively larger in(1-IO!-Lm ). size (5-100 !-Lm).

2. The nuclear material is undefined having no 2. A true nucleus having a nuclear membranenuclear membrane and is called nucleoid. is present.

3. A single chromosome is present. 3. :\1ore than one chromosome is presenL

4. It does nm contain membrane-bound cell 4. It contains membrane-bound cell organellesorganelles. like mitochondria, plastids. etc.

5. Ribosome is of 70S type. 5. Ribosome is of 80S type.

6. Cell division takes place by fission or 6. Cell division lakes place by mitosis orbudding or fragmentation. meiosis.

The Fundamenlal Unit of Lde 39

'.._ T>k,. ,~: ~-

•Phagosome

PseudopodiaT

Foodparticle

1Amoeba

12. What would happen if the plasma membrane ruptures or breaks down?

Ans. Plasma membrane is the selectively permeable membrane that surrounds the cell and allowsthe entry and exit of selected materials of the cello If it ruptures, the contents of the cell willcome in direct contact with the surrounding medium and not only unwanted material willbe able to enter freely into the cell, but useful material will also find its way out of the celleasily. This will seriously disrupt the various metabolic activities of the cell and will result inits eminent death,

13. What would happen to the life of a cell if there were no Colgi apparatus?

Ans. If there were no Golgi apparatus, the material synthesised by endoplasmic reticulum wouldnot be carried to the various parts inside and outside of the cello Also as the Golgi apparatusperforms the function of storage and modification of the material synthesised in the cell,these materials could not be stored and modified further

Moreover, there will be no production of lysosomes which will cause the accumulation ofwaste material, viz., worn out and dead cell organelles within the cell which will ultimatelylead to cell death.

14. Which organelle is known as the powerhouse of the cell? Why?

Ans. Mitochondria are known as powerhouse ofthe cell because these are the sites ofcellular respiration.They release energy in the form of ATP (Adenosine Triphosphate) oxidation of carbohydratesand fats. This energy is then utilised by the organelles to carry out their basic functions.

15. Where do the lipids and proteins constituting the cell membrane get synthesised?

Ans. Lipids are synthesised in smooth endoplasmic reticulum from where they are transported tothe cell membrane.

Proteins are synthesised by the ribosomes in the cytoplasm. These are then transferred toGolgi complex and ER for further modifications from where they reach their destinations.

16. How does an Amoeba obtain its food?

Ans. In Amoeba, the food particles get surrounded by a cell membrane invagination called pseudopodia.The pseudopodia d,en merge with each other forming a food vacuole which is engulfed into thebody ofAllweba. These vesicles are called phagosomes where the food is digested.

17. What is osmosis?

Ans. The diffusion of water or solvent through a semi-permeable membrane from a solution oflower concentration of solutes to a solution ofhigher concentration ofsolutes is called osmosis.

18. Carry out the following osmosis experiment:

Take four peeled potato halves and scoop each one out to make potato cups. One of thesepotato cups should be made from a boiled potato. Put each potato cup in a trough containingwater.

Now,

(a) Keep cup A empty

(b) Put one teaspoon sugar in cup B.

(c) Put one teaspoon salt in cup C.

(d) Put one teaspoon sugar in the boiled potato cup D.

-----Ilfj~';JIil~.... ,. ~

40 The Fundamental Unit of life

Keep these for two hours. Then observe the four potato cups and answer the following:(i) Explain why water gathers in the hollowed portion of Band C.

(ii) Why is potato A necessary for this experiment?

(iii) Explain why water does not gather in the hollowed out portions of A and D.

Ans. (i) Water gathers in the hollowed portion of Band C because of the process of endosmosis(moving in ofthe solvent). The potato wall acts as a semi-permeable membrane. As the cupsBand C are filled with sugar and salt respectively and their outer part is in contact withthe water, the concentration of water outside the cups is higher than inside the cups. So,water l110ves fronl its higher concentration towards the lower concentration, i.e., insidethe cup.

CupA

~j

CupS CupC

Fresh peeled I Sugar

-"" I~

\Cup 0

(ii) Potato A acts as a control of the experiment. It is very necessary for comparing the resultsof the experiment. It shows that if the concentration of water is same on both sides, therewill be no movement of water.

(iii) Water does not gather in the hollowed out portions of A as it does not contain hypertonicsolution so there is no concentration difference and hence no movement of solvent. Waterdoes not gather in the cup D as the cells of boiled potato are dead and the potato wall isno longer semi-permeable. Hence, no osmosis occurs.

HOTS (Higher Order Thinking Skills)

1. Ifyou are provided with some vegetables to cook, you generally add salt into the vegetables.After adding salt, vegetables release water. Why?

Ans. When salt is added, a hypotonic medium is created, i.e., the concentration of salt moleculesis more outside the vegetables than inside. Hence, due to osmosis water from the vegetablescome out.

2. If cells of onion peel and RBC are separately kept in hypotonic solution, what will happento each of them? Explain.

Ans. When kept in a hypotonic solution, the onion cells will become turgid because the water willenter the cell due to osmosis. But the cell wall present outside the cell provides it rigidity anddoes not let any harm to occur.

Whereas, in RBC the movement of water inside the cell due to osmosis will lead to burstingof the cell because it does not have a rigid cell wall.

3. How will absence of anyone of the cell organelles affect the cell's working?

Ans. Functions of all the organelles are inter-linked to each other and ultimately to the working ofthe example cell. So, if even a single link is missing, the cell ultimately suffers and dies. Fore.g., DNA from the nucleus passes the information for protein formation to the ribosomeswhich send the proteins to Golgi complex and ER for modification and transport.


4. Where will you find more number of ribosomes-in cancer cells or in fat cells?

Ans. Ribosomes are found in greater number in actively dividing cells which are the cancer cells asthey need more amount of proteins for the formation of new cells.

5. A solution of 3% glucose and a solution of 8% glucose are kept in a trough separated by asemi-permeable memhrane. What will you observe after I hour?

Ans. After I hour, the solutions on both the sides of the semi-permeable membrane will becomeisotonic because of the process of osmosis.

EXERCISES

A. Very Short Answer Questions (1 m.ark)

I. Who first discovered the cell?

2. Who discovered the cytoplasm and nucleus'

3. Which type of cell is found in bacteria and blue-green algae?

4. Write down the names of cell organelles of eukaryotic cells.

5. What is the main characteristic of prokaryotic cell?

6. Write down the full form of ATP

7. Write the names of cell organelles.

8. What are the three major functional regions of the cell?

9. Is the cell wall living or dead in plants?

10. Write down one main function of the following cell organelles:

(a) Plasma membrane (b) Chloroplasts

(c) Nucleus (d) Mitochondria

(e) Nucleolus (j) Chromosomes

(g) Ribosomes (h) Lysosomes

(i) Goigi apparatus !j) Peroxisomes

11. Is chloroplast a non-living structure?

12. Name the nucleic acids present in the nucleus of an animal cell.

13. What is the function of mitochondria'

14. Which cell organelle releases the energy in the form ofATP?

15. j arne the chemical molecule which carries the hereditary characters from parent to offspring.

16. Do the plant cells contain a centriole?

B. Short Answer Questions (2,3 marks)

I. Who coined the word 'cell' and how'

2. What is the cell theory?

3. Write down the names of cell organelles and describe the functions of any two.

4. Differentiate between:

(a) Ribosome and centrosome,

(b) Chromatin and chromosome,

(c) Nucleus and nucleolus,

(d) Haploid and diploid cells.

Tenlal Unit of life

5. What is the difference between cell wall and cell membrane?

6. What is a cell? Describe its shape and size.

C. Long Answer Questions (5 marks)

1. Why are mitochondria called the power-house of a cell? Describe the structure and functionsof mitochondria with the help of suitable diagrams.

2. What are the major types ofplastids? Describe the green plastids involved in photosynthesis.

3. Describe the structure and functions of Golgi apparatus.

4. What is digestive bag? Describe its structure and functions.

5. Write down the names of two nucleic acids. What are their functions?

6. What is gene and where is it found? Give its functions.

7. What will happen if we put a plant or animal cell in a

(a) hypotonic solution (b) hypertonic solution (e) isotonic solution?

8. What is diffusion? How is it useful in living beings?

9. Draw diagrams of different kinds of cells present in human body.

10. Describe the main parts of a typical cell with various functions of the parts.

D. Practical-based Multiple Choice Questions

1. In order to observe a slide under high power, a particular sequence is to be followed afteradjustment of light with the help of mirror and condenser. Identify the correct sequence.(i) Focus the slide with the help of coarse adjustment

(ii) Focus with the help of fine adjustment

(iii) Put the slide on stage

(iv) Rotate the nose piece, to place the objective with high power on the slide

(a) (ii), (iv), (iii), (i) (b) (iii), (i), (iv), (ii)

(e) (iii), (i), (ii), (iv) (d) (iii), (ii), (iv), (i)

2. Rima of Class IX was asked to prepare the slides of onion peel and cheek cells in the labbut she was highly confused to see five different types of stains on the shelf of chemicals.As a helpful classmate, what stains would you suggest her to use for different slides?(a) Methylene blue for onion peel & safranin for cheek cells

(b) Acito carmine for onion peel & janus green for cheek cells

(e) Leishman stain for onion peel & eosin for cheek cells

(d) Safranin stain for onion peel & methylene blue for cheek cells

3. Four students . Sharukh, Amir, Salman and Sanjay were provided with microscopeshaving different eye pieces and objective lenses. They were told to fit the eye piece andobjective lens to get the magnified view of the object. Who do you think got the maximummagnification?(a) Amir selected objective of value 45X and eyepiece of value 5X

(b) Shahrukh selected objective of value lOX and eyepiece of value 20X

(e) Salman selected objective of value 40X and eyepiece of value lOX(d) Sanjay selected objective of value 20X and eyepiece of value 15X

4. An over enthusiastic student scrapped the inner side of his cheek to get a few epithelialcells with the help of a dissecting needle. Without feeling any pain, he could take out thecells and also prepared an excellent slide which fetched him full marks in his exam. Hedeveloped infection in his mouth after some time because(a) he must be having the infection before


(b) may be he pricked very hard

(c) the needle was not sterilised

(el) all of the above

5. Following diagrams show the temporary mount of onion peel prepared by different student(A, B, C, D) of St. John's school. Who do you think was the most attentive student of thisclass as he followed all the instructions given by his biology teacher?

I I(a) (b)

...-I Ln-~

(c) (d)

6. Many inquisitive students of Class VIII prepared a temporary mount of onion peel to lookfor a centrally located nucleus in a cell. They were disappointed when they could not seeit. Their mistake was(a) not adding safranin on the peel

(b) they took the outer peel instead of inner peel

(c) nucleus is visible only under high power and they observed it only under low power

(el) peel must have got overlapped reducing the contrast

7. Given below are the steps for the preparation of a temporary mount of onion peel. Thesteps are however not arranged in an order. Arrange them in a correct sequence.(i) Examine the slide under the microscope

(ii) Put a cover slip, press it gently and clean the slide.

(iii) Remove a thin transparent peel from a piece of onion.

(iv) Transfer the peel on a clean slide with the help of brush and needle.

(v) Put few drops of safranin stain in the watch glass to stain the peel.

The correct sequence would be(a) (iii), (v), (iv), (ii), (i)

(b) (v), (iv), (ii), (iii), (i)

(c) (i), (ii), (iii), (iv), (v)

(el) (ii), (iv), (v), (i), (iii)

8. Given below are four operations for preparing a temporary mount of human cheek cells.(i) Taking scraping from inner side of the cheek.

(ii) Putting a drop of glycerine on the material.

(iii) Adding two or three drops of methylene blue.

(iv) Rinsing the mouth with fresh water and disinfectant solution.

The correct sequence of these operations is(a) (i), (ii), (iii), (iv)

(b) (iv), (i), (iii), (ii)

(c) (iv), (i), (ii), (iii)

(d) (i), (iii), (ii), (iv)


9. Which of the following is a correctly labelled cell of an onion peel?Nucleus --. ...... Nucleus

Cell '-~, - / '-~ ! - ,-Cellwall

membrane

Cell wall=fis-.--~ .'----. 6 0 ~cell, ., '. membrane

Vacuole ' .,: ! :

'._. _.. ' '

Vacuole(a) (b)

Nucleus--, Nudeus-, -Vacuole

Cell wall

~o............iceRwaJl

Gell ~'---'-. J0' .membrane ' :

'. -" --- .-'Vacuole

(c) (d)

10. Arrange the following steps in correct sequence.(i) Putting a drop of glycerine on the cheek cells on a slide.

(ii) Scrapping the inner side of cheek

(iii) Adding methylene blue stain, and(iv) Placing the cover slip over the material.

(a) (i), (ii), (iii), (iv) (b) (ii), (i), (iv), (iii)

(e) (iv), (ii), (iii), (i) (d) (ii), (iii), (i), (iv)

II. Nikita observed a slide of human cheek cells under a microscope in its (i) low magnifyingpower, (ii) high magnifying power settings. In the first setting, she must observed(a) fewer cells in a darker field of view (b) more cells in a brighter field of view

(e) more cells in a darker field of view (d) fewer cells in a brighter field of view.

12. To observe cells in an onion peel, we must prepare the slide by mounting on it(a) crushed pulp of onion (b) dry scale leaf(e) green leaf of onion (spring onion) (d) thin layer of Oeshy leaf of onion.

13. Human cheek cells stained in methylene blue and mounted in glycerine were observedwith the help of a compound microscope. The components of the cell which would be seenare(a) Cell wall, cytoplasm, nucleus(b) Plasma membrane, cytoplasm, nucleus

(e) Plasma membrane, cytoplasm, nucleus, mitochondria

(d) Plasma membrane, cytoplasm, nucleus, mitochondria, golgi body, lysosomes.

14. Trupti was observing an onion peel stained with safranin under a microscope. The colourof the cell wall appeared(a) deep blue. (b) black

(r) pinkish red (d) "dim,'.

15. Nucleus in eukaryotic cells is centrally positioned becausevI) it is lhe regulatioll Cl'llIre orlhe cell

(II) it conlitins n'\--"(r) it has to send the illii.JrIlI;tlioll L'qll~t1I~ ill all dinTlioll ...

(rI) it rt'q(lirl'~ Illaxilllllill protcnioll duc 10 ih kL'\ fiIIH·li(JJl~


(b) Cytoplasm(d) Mitochondria

(b) Large vacuoles

(d) Centrioles

(b) Glycerine

(d) Methyl alcohol

18. Maximum light passes through the microscope when(a) aperture is closed and objective is 40X

(b) aperture is open and objective is 40X

(e) aperture is open and objective is lOX

(d) aperture is partially open objective is 40X

19. The scientist, who invented the first compound microscope was(a) Zacchrais Janssen (b) Leeuwenhoek(e) Knoll and Ruska (d) Robert Hook

20. If cheek cells are placed in 10% salt solution, they will(a) absorb water and salt and become bigger in size

(b) no change will occur

(e) shrink as the cells will lose water due to exosmosis

(d) cells will die

21. Which of the following liquids is not used in the preparation of stained temporary mountof onion peel?(a) Water

(e) Safranin

22. Pick the odd one out.(a) Plastids(e) Cell wall

16. Excess ofstain from the slide can be removed by(a) using a muslin cloth (b) using a blotting paper

(e) using a polythene (d) using a handkerchief

17. Which of the following organelles is not visible in the slide of onion peel even under highpower?(a) Cell membrane

(e) Cell wall

Answers

1. (b) 2. (d) 3. (e) 4. (d)

5. (a) 6. (b) 7. (a) 8. (b)

9. (b) 10. (d) 11. (b) 12. (d)

13.(b) 14. (e) 15. (d) 16. (b)

17.(b) 18. (b) 19. (b) 20. (e)

21. (d) 22. (d)

III

The Fundamental Unit of LITe

Chapter: Two

UDs)s)lliJ~s)

In the earlier chapter, it has been described that all living organisms are madeof cells. A unicellular organism, such as Amoeba, Pammeciurn, has a single cell inits body. The single cell performs all the life activities, e.g., movement, intake offood, digestion, respiration, reproduction and excretion, etc. But in multicellularorganisms there are millions of cells. Most of these cells are specialised to carry outa few functions. Each specialised function is taken up by a different group of cells.These cells function very efficiently. Thus, cells of multicellular organisms showdivision of labour. For example, in human beings, muscle· cells contract and relaxto cause movement. Nerve cells carry messages. Blood cells carry oxygen and CO2,

In plants, vascular tissues (xylem and phloem) conduct water and food. So, we seethat cells, that are specialised in one function, are grouped to form a tissue. Blood,muscles, xylem and phloem are all examples of tissues.

A tissue is defined as a group ofcells ofcommon origin having similar structureand specialised for performing a common function.

In the beginning, all the cells are alike but as development proceeds, a changeoccurs in their size, structure and functions; this differentiation of cells is followedby the formation of different kinds of tissues. Thus, a tissue is a cluster of cells ata definite place in the body performing a special function. A group of tissues ofdifferent types work in harmony to form organs.

I Are Plants and Animals Made of Same Type of Tissues?

Plants and animals are two different organisms. Plants are autotrophicorganisms, i.e., they prepare their own food by the process of photosynthesis.Moreover, plants are stationary or fixed, i.e., they do not move about except for afew unicellular algae. Hence, they do not consume or need much energy, therefore,most of the tissues of plants are supportive, that provide them with structuralstrength. Most ofthese tissues like xylem, phloem, sclerenchyma and cork are dead,i.e., they do not contain living protoplasm.

On the other hand, animals are heterotrophic organisms. They move fromplace to place in search oHood, mate and shelter. Therefore, they need more energyas compared to plants. Most animal tissues contain living cells.

There are some tissues in plants that divide throughout their life. Tissuesdivide for the growth hand reproduction of plants. Such tissues are localised incertain regions. Based on the dividing capacity of the tissue, the various plant tissuescan he classified as meristematic tissue and permanent tissue. On the other hand,there is no such distinct region in animals. Cell growth in animals is more uniform.So, there is no such demarcation of dividing and non-dividing regions in animals.

• A tissue is a groupof cells having acommon ongm,similar structureand specialised toperform a commonfunction.

Tissues 47

Plant Tissues

Plant tissues have been classified into two main groups: growing or me.ristematictissues and permanent tissues. Growth in plants is restricted to certain regions.

t" Classification of Plant Tissues ./

Il

·Totipol~t ulh an fiJjJGbf~of rrins: ris~ 10 0.8 IhI'G'riOIl$ uU t'ftWs of th~ body':! an f1rgQ~~s~"--- -. oJ

Phloem1. Sieve lubes2. Companion cells

Xylem1. Xylem vessels2. Tracheids

lComplex

(Conductingtissue composed of

more than onetype of cells)

Permanent Tissues(Mature cells incapable of

cell diVision)

fSimple

(Protective andsupporting

tissues composed ofsimilar type of cells)

I

Parenchyma

Collenchyma

Sclerenchyma

Intercalary(Internodes

of stem)

Lateral(Below bark,cambium. indicot roots

\ and stems) J

Meristematic Tissues(Cells are capable of cell division

and have totipotency·)

f l t\

Apical(Tips of

root\ and stem) I

Ir.tercalarymeristem

Apicalmeristem

I A. Meristematic TissuesThese are found in the growing regions of the plant, e.g., shoot tip, root tip and

cambium. Their cells are immature and are capable of undergoing repeated divisionthroughout their life. These cells are spherical, oval, polygonal or rectangular inshape. Their cytoplasm is dense, cell ,,·all is thin, nucleus is single and large, andvacuoles (single or few or no vacuoles) if present are smaller. I ntercellular spaces arelacking. This tissue continuously forms a number of new cells.

Classification: According to their position on the plant body, they are of thefollowing types:

(a) Apical meristem,(b) Lateral meristem,

(e) Intercalary meristem.

(a) Apical meristem: It is found at the growing tips of stems (shoot) androots. Its cells are roughly spherical, alike and divide continuously toform new cells which later differentiate into epidermal tissue, groundtissue (cortex) and vascular tissue (vascular bundles). Thus, the root andstem of a plant grow in length (primary growth). Root tip is protectedby a root cap formed of a layer of cells. It protects the root tip fromIIlJury.

(aJ (b)Fig. 22 Seeuun through (a, stem ape) ar.d

b! root lip showing rnerislemallc JSSlM

lateralmeristem

Fig.2.1 Menstems based On poslbon

iiiIIillI 48 Tissues

(b)

-- Dermatogem(epidermis)

Plerome·--';---'----.!-(vascular bundles)

-F--Periblem(cortex)

Fig. 2.3 L.S. of stem tip

Cellwal

FIg. 2.4 1.5. of the growing tip of root

(c) Intercalary meristem: It is a part of the apical meristem, which is separatedfrom the apex during the growth. It is found at the base of the leaves orinternodes (on either side of the node on twigs). In grass and bamboo, theyare found near the nodes. They increase the length of the organ.

activity 1• Take two glass jars, A and B, fill thern with water.• Take two onion bulbs and place one onion bulb on the rnouth ofeach jar (as shown in Fig. 2.5).• Obseroe the gTOwth ofroots in both the onion bulbs for a few days.

• Measure the length ofroots on day 1, 2 and 3.• On day 4, cut the tips (about 1 crn part) ofroots in one bulb ofjar A.• Again obseroe the growth of roots in both the jars and rneasuTe thei,· lengths each day for

five lIlore days and record yOUT observation in the following table:

Length of root Day 1 Day 2 Day 3 Day 4 Day 5

I. Jar A

2. Jar B

• PrOlll the above observation, answer the following questions:(i) Which of the jars has longer roots? Why?

(ii) Do the roots continue l5'·owing even when you have Temoved theiT tips?(iii) Why do the TOot tips stop growing in jaT A after you have cut them?

• Roots of onion bulbs in jaT B will continuously grow and will become 10ngeT because theyhave dividing cells at the TOot tip. In jar A, theTe will be no growth in onion bulb roots,since they lack the dividing cells. Cut TOots stop l5'·owing in jar A since thel"/! is no dividingtissue p,·esent.

What happens to the cells formed by the meristematic tissue?

They take up a specific role and lose the ability to divide. Thus, they form a typeof permanent tissue. This process of taking up a permanent shape, size and functionis called differentiation. In this way, the cells of meristematic tissue differentiate toform different types of permanent tissues.

To understand the structure and function of various types of permanent planttissues, YOil have to study the anatomy (Greek; ana = up; ternnein = to cut) of plantorgans like roots, stem, leaves, flowers, etc.

JarA Jar8

Fig. 2.5 Growth of roots inonion bulbs

Tissues 49

activity 2

-.---.--~J11

• Take a small po,-tion ofa sunfloweT stem.• Keep it in wate,- in a watch glass.• Cut its very thin sections with the help ofmzo,- 0,- blade.• Now, stain the slices with safranin.• Tmnsfe,- one neatly cut section on a slide, and put a d,-op ofglycerine.• COVeT it with a cover-slip and obseroe under a micTOscope.• You will obseroe diffe,-ent kinds of cells and thei,' m-mngement. Compa,-e it with Fig. 2.6.

TrichomeMucilaginous canal

Cuticle~--- Epidermis

~;:::::= Hypodermis~ Cortex --'

I±!!L---_ Endodermis

Pericycle--~

Fig. 2.6 Section of a stem

On the basis ofyour observation, try to find out the answer to the following questions:

(i) Are all cells similar in structure?

(ii) How many types of cells can be seen?

(iii) Can you think of reasons why there would be so many types of cells?

You will find that the section ofsunflower stem contains seven different types ofcells and all these cells perform different functions such as, xylem (conducting water),phloem (transport of food), epidermis (protection), collenchyma, sclerenchyma(support), parenchyma (food storage), and cambium (growth). Thus, from theabove activity, you have learned that different groups of cells of tissues present in aplant organ help to perform different functions. You can also try to cut sections ofstems and roots of different plants and study them.

I B. Permanent Tissues

These are derived from the meristematic tissues. Cells formed from thedivision of meristematic tissues, after maturity form permanent tissue. Their cells donot divide further. They gradually become specialised. They have a definite shapeand may be living or dead and thin or thick walled. Their cytoplasm is vacuolated.Permanent tissues are of two types: simple tissue and complex tissue.

PhloemSclerenchyma

Permanent Tissue...---_...._--.Simple Complex.. ..

.J-....~XylemCollenchymaParenchyma

'-

IIL3 -'v

VK Biology IX 50 Tissues

(b)

FI9 2.7 I.a) 1S. of Parend1yma (b) L.S. of Parenchyma

f--- Nucleus

+--- Cytoplasm

•-=+--- Vacuole

• •~~~-"rt----lntercellular space

]f------- Primary cell wall

Intercellular spaces

(a>

1. Simple Tissues

These are ofthree types: (a) parenchyma, (b)collenchyma and (c) sclerenchyma.

(a) Parenchyma (Gr., pam, beside + enchyma, in-filling). Parenchyma is generallyfound in all plants. Its cells are living. Each cell has a thin cell wall of celluloseand encloses a dense cytoplasmwhich contains a small nucleusand surrounds a large centralvacuole.Generally its cells arerounded, oval, polygonal orspherical in shape. The cellshave intercellular spaces filledwith air. These cells are foundin epidermis, cortex, pith,pericycle, elc., of stems, roots,leaves, flowers and fruits (inpulp). It is also found in xylemand phloem.

Functions(i) They function as a packing tissue, filling the spaces between other tissues.

They maintain the shape and firmness of the plant due to turgidity (providemechanical strength to the plant).

(ii) Their cells store food materials such as starch stored in the parenchymacortex of potato tuber.

(iii) Parenchyma cells store excretory products such as gum, tannin, resins,crystals of inorganic waste, etc.

(iv) Parenchyma in xylem and phloem conducts water and food materialrespectively.

(v) Some parenchyma cells have the power to divide and form secondarymeristems.

(b)

Fig. 2.8 la) TS. of Collenchyma Ib) L.S of Collenchyma

---Endwall--- Cytoplasm

LPrimary celt wall(thickened atcorners)

I Nucleus

-----L- Vacuole

J Chloroplast

~i""~-~~---lntercel1ularspace

Nucleus

$;;'--- Cell wall

(al

(vi) Parenchyma called aerencl1\'ma in aquatic plants helps in aeration oftissues and in aquatic plant it also provides buoyancy to help them float.

(vii) They also contain chloroplasts called chlorenclnma which are responsiblefor photosynthesis (formation of starch).

(b) Callenchyma (Gr., Kalla, glue). Cells are oval or polygonal in shape andgenerally found below the epidermis of the dicotyledon stem and petiole(leaf stalk). They are closely packed together and hence, no intercellularspaces. Their cell walls aremuch thickened at the corners(due to cellulose and pectin)where a number of cells jointogether. The cells are livingand vacuolated. Cell wall isirregularly thickened due towhich the plant becomes firmand elastic. Sometimes thesecells contain chloroplasts. Inherbaceous plants, it acts as apermanent mechanical tissue.It is absent in monocot stems,roots and leaves.

t:--iI-_T.:;:iS:::.SU::::8.::..S ..::51:..-';;;;;;;;;::=:":"mi'l

••• 1.....--.

Fig. 2.9 :a'i IS. of ScIerenchyma (b) loS. of ScIerenchyma

Lignifiedthick wall

(b)

In'l---Narrow lumen

Simplepit pair

(a)

Functions:(i) Being flexible in nature, it provides tensile strengtb to the plant body.

(ii) It provides mechanical support to the leaf where it occurs on both sides ofvascular bundles or as isolated patches.

(iii) It renders suppleness to the various parts of the plant (leaf, stem).(iv) When chloroplasts are present it takes part in photosynthesis.

(c) Sclerenchyma: It is also asimple permanent tissueand provides mechanicalsupport to the plant.These are considerablythick-walled and lignifiedwith simple or borderedpits in their walls andare characterised bythe absence of livingprotoplasts. On the basis ofvariation in form. structure,origin and development,these may be either fibres or sclereids (see Fig. 2.9).Fibres: They exist as long, narrow and pointed cells. They occur in groups, as

sheets or as cylinders in various parts of tbe plant body in and around the vasculartissue, and may also develop below the epidermis a cylinder of supporting tissues insome older stems.

Sclereids: Sclereids are very thick walled, hard and strongly lignified. Theyare mostly isodiametric, polyhedral, short and cylindrical. These are dead cells withvery narrow cell cavities (lumen) due to excessive thickness of the cell wall. Sclereidsmay occur singly or in groups in stems, leaves, fruits and seeds.

Fibres and sclereids are tbick-walled. The 'cells' consist of walls alone, for thecell contents die when the walls become thickened and impermeable, cutting offnutrients and water. The walls are composed oflayers of cellulose impregnated withlignin (a chemical substance which acts as cement and hardens them). Lignin, whencombined with cellulose, resists stretching (has high tensile strength) and buckling(has high compressional strength). Often these walls are so thick that there is nointernal space inside the cell.

Function:(i) Protects the plant from stress and strain ofenvironmental forces like strong winds.

(ii) Provides mechanical strengtb and rigidity to the plant.(iii) Sclereids provide grittiness to the pulp of fruits.

Table 2. I Comparison of Collenchyma and Sclerenchyma

Collenchyma Scelerenchyma

I. Living cells. \. Non-living cells.

2. Cytoplasm is present in the cells. 2. Cell's cytoplasm dries up on maturity.

3. Cell walls are formed of cellulose. 3. Cell's walls are lignified.

4. Cell wall thickening is not uniform, much 4. Cell wall thickening is uniform.thickened at corners.

5. Cell lumen is wide. 5. Cell lumen is narrow due to thickeningof cell wall.

6. Gives mechanical support and elasticity to 6. Gives only mechanical support.the plant.

52 Tissues

activity 3• Take a freshly plucked leafofRhoeo plant.• Stnitch its upper side and break it with applying pTeSsure.• When breaking it, stretch gently so that some peel or skin projects out.• Keep this peel in a pelridish filled with water.• Add a few drops ofsafranin stain to it.• After a few minutes transfer it onto a clean slide.• Cover it with a cover-slip and obse11Je it under the micTOscope.

.....

Ruptured epidermis

Cork cambium(phellagen)

FIQ 2.10 Protective bssue

Cork cells

Fig.2.11 Cuticle and few cells of epidermis

Fig. 2,12 Astoma (open and closed} and guard ceDs

.:.0 _.":.-. -::. -:.-

Cor\<(phellem)

-.J

L~ l-'

-----l J" J I ::'>.~-z,. ] 1i--<. k

~ J

You will observe that this outermost layer of cells in leaves is a single layer.These form the peel of an organ, the epidermis.

Protective Tissues

These tissues are usually present in the outermost layer ofthe plant body. This layer is one cell thick, covered with cutin.These tissues protect the inner tissue of the plant body. Example isepidermis and cork (or phellem).

(a) Epidermis: It is present on the external surface on all theplant organs (e.g., leaves, flowers, stem and roots) in the formof a layer. It is a protective layer. Its cells are like parenchymaand lack intercellular spaces. The epidermis is usually onecell thick but it is multilayered in some plants, like Ficus,NeTium and orchids. Some plants possess hypodermis belowthe epidermis. On the outer surface of epidermis, a waxy layerof cutin is present. It is called cuticle. It minimizes or checksthe loss of water from the internal tissues and also protects themechanical injury and invasion by parasitic fungi. It is not found in aquatic plants.

Each cell possesses peripheral protoplasm, a nucleus and a large centralvacuole. Their shape is variable. They are living cells like parenchyma.

Stomata: In between the epidermal cells are present minute (~I~S~~)

apertures, called the stomata. Each stoma (singular) is guarded -l.by two kidney-shaped cells called the guard cells. Guard Epidermal

cells are the only epidermal cells which contain chloroplast, cell

the rest being colourless. The expansion and contraction ofthe guard cells regulate the opening and closing of stoma.Stomata are necessary for exchange of gases (02 and CO2)with the atmosphere. It allows gaseous exchange to occurduring photosynthesis and respiration. During transpirationtoo, water vapour also escapes through stomata. Duringthe process of photosynthesis, CO2 is taken by the stomatafrom the atmosphere and O2 is released as a byproduct. While during therespiration of plant, 02 is taken and CO2 released via stomata. Photosynthesisoccurs in day time (in the presence of light), but respiration occurs both in dayand night time. .

The process of transpiration helfls the xylem tissue conductwater and dissolved mineral salts by mass flow mechanism.

(b) Cork (or Phellem): Due to gradual thickness in diameterof dicot stem and root, the outer peripheral cells form thecork cells or phellem. These cells are arranged in radial rows.The cork cells have no intercellular spaces. These cells after

Fig. 213 Co", or Phellum (IS.)

Tissues 53

~~--~~---~~----~",,".. , .

differentiation become dead. A fatty substance, suberin is deposited in the cellwalls, due to which their walls become thickened. These cells are impermeableto water and gases. The cork cells also do not have protoplasm and nucleusand are filled with resin or tannin. Their function is to prevent loss of waterfrom the internal tissues.After the formation of cork tissues, the cortical region (i.e., cortex) is not ableto get water and nutrients, consequently its layers dry up and fall down. Inonion bulb, the skin ofonion becomes thick and water-proofdue to depositionof suberin.

Cytoplasm

I

1+-- Nucleus

I

I

I

(c) Xylem parenchyma

o

(b) Vessels

Fig. 2.15

"is'.

2. Complex Permanent Tissues

They are permanent tissues which contain more than one type ofcells. All thesecells coordinate to perform a common function. XYlem and Phloepl are examplesof such complex tissues. Xylem and phloem are both conducting tissues and areknown as vascular tissues: together both & of them constitute the vascular bundle.Vascular or conductive tissue is a distinctive feature of the complex plants, one thathas made possible their survival in the terrestrial environment.

The function of vascular bundles is to conduct water, mineral salts and solublefood materials to the different parts of the plant body.

(i) Xylem: It is a complex tissue that forms a part of vascular bundle. It is mainlyconcerned with the conduction of water and minerals and also providesmechanical support to the plant.As a conducting strand, xylem forms a continuous channel through the roots,stem, leaves, flowers and fruits. It consists of four different types of cells, bothliving and non-living. The four component of xylem are:(a) Tracheids (b) Vessels (tracheae)

(c) Xylem parenchyma (d) Xylem fibre (sclerenchyma)(a) Tracheids: These cells are elongated with pointed chisel-like ends. Their

walls are thick and lignified.They conduct water anddissolved substances fromthe roots to the leaves.

(b) Vessels (tracheae): Thesecells are also elongatedtube-like, and placed endto end. Their partitionwalls are either perforatedor completely disappearforming an elongated tube.The main function of thesevessels is the conduction (a) Tracheidsof water and minerals liketracheids.

(c) Xylem parenchyma: Their cells are living and thin or tluck due to thedeposition oflignin. Their function is to store reserved food (starch) and helpin the sidewise conduction ofwater upward mrough tracheids and vessels.

(d) Xylem fibre (sclerenchyma): These are elongated and pointed at both meends. Their walls are also thickened due to deposition of lignin. Exceptxylem parenchyma, the other three types of cells are dead and their wallsare pitted. Function of xylem fibre is to giYe mechanical support to thexylem tissue.

Fog. 214 Xy~m

• Xylem cells conductwater and salls fromroots to leaves.

• Xylem tracheUls,tracheae and xylemfibre are elongatedand dead.

54 Tissues

Table 2.2 Differences between Tracheids and Vessels

S.No. Tracheids Vessels

I. These arise from a single cell. These arise from a number of cells.

2. Their ends are tapering or oblique. The ends are rounded or transverse.

3. The lumen is narrow. The lumen is wide.

4. Their walls are more thickened. Their walls are less thickened.

Fig, 2.16 T.S. of a phloem tissue

Section of PhloemFig. 2.17 T.S. of a phloem tissue

II , Companion11- ~ cell

• Phloem conductsfood materials fromleaves to differentparts of the plant.

Companion cell

i Sieve tube

0 -'-'-' 0 .00'--'001&tj Sieve plate

I - Sieve tube

t \1 I, Phloem

'<:le>O

k '"~ Parenchyma cell'.:n-.:;::.-, Nucleus of

parenchyma cell

Phloem: Phloem is another type of complex tissue. Itaids in the conduction of food such as amino acids andcarbohydrates from the leaves down the stem, trunk,roots and other parts of the plant body. It is also calledbast. It is composed of four types of cells (see figure):(a) Sieve tubes

(b) Companion cells

(e) Phloem parenchyma

(d) Phloem fibres or bast-fibres ,(a) Sieve tubes: The sieve tubes are composed of living, .Sieve plate

. With sIeve poresslender and elongated tube-hke cells placed end toend. The cell walls are thin and made up of cellulose.The transverse walls are obliquely placed and perforated by a numberof pores called sieve plates. Due to these perforations between adjacentcells, dissolved food materials move from one cell to the other. The foodmanufactured by leaves is transported to food storage organs (cortex) ofthe plants. Their cells have a parietal layers of cytoplasm and are withoutnucleus. In the centre of each cell a large vacuole is present.

(b) Companion cells: Long narrow, living, elongated cells are usuallyattached with the lateral side of sieve tubes called companioncell. Their lateral walls are thin and pitted and through thesepits the cytoplasmic connection between sieve tubes andcompanion cells is established. The companion cells havecytoplasm and a large nucleus. Companion cells are supposedto help in the transport of food along with the sieve tubes.

(c) Phloem parenchyma: These cells are like ordinary parenchymathe cells are living. They are intermingled with sieve tube. Theirfunction is to store food material and help in the transport offood.

(el) Phloem fibres: These are sclerenchymatous cells. Thesecells are elongated, pointed, lignified and dead. They givemechanical support to the plant. They are used for makingropes and rough cloth.

(ii)

Table 2.3 Comparison of Xylem and Phloem

S.No. Xylem Phloem

I. It is a complex tissue. It is a complex tissue.

2. Except xylem parenchyma, all other Except for phloem fibres, phloemxylem elements (sciereids, tracheae and cells are living.xylem fibres) are dead.

3. Conducts water and minerals from Transports manufactured food fromfOOts to leaves, etc. leaves to storage organs and growing

parts of the plant body.

Tissues 55 iUii@

Table 2.4 : Comparison of Meristematic and Permanent Tissues

S.No. Meristematic tissues Permanent tissues

I. Simple tissue. Simple or complex tissue.

2. Cells divide repeatedly. Cells are derived from meristematictissue and do not divide.

3. All cells are alike (undifferentiated). Cells are differentiated into vanoustypes.

4. Cells are isodiametric, i.e., all sides are Cells are of various shapes and sizes.equal.

5. Intercellular spaces are lacking. Intercellular spaces are present.

6. Cell walls are thin. Cell walls may be thin or thick

7. Vacuoles are not found Vacuoles present in mature cells.

8. Metabolically very active Metabolically not active.

FORMATIVE ASSESSMENTFA 2.1: Match the Following

Match the terms given in column I to their meaning in column II.

Column I Column II

(a) Collenchyma

(b) Chlorenchyma

(c) Aerenchyma

(d) Sclerenchyma

(e) Apical meristem

if) Lateral meristem

(g) Complex tissues

(i) Permanent tissue which makes theplant hard and stiff

(ii) Large air spaces or cavities present inparenchyma tissues to give buoyancyto the plants

(iii) Permanent tissue that providesflexibility to the plant

(iv) Chlorophyll-containing parenchymacells.

(v) Xylem and phloem

(vi) Increases length of the stems and theroots

(vii) Increases the girth of the stem or root

Classification of Plant Tissues" /

Fill in the blanks given below to complete the classification table.

Permanent Tissues

Intercalary

Meristematic Tissues

.--!----,.Apical

FA 2.2: Flow Chart-based Worksheet

56



1. Meristematic tissue is the dividing tissue present in the growing regions of theplant.

2. Permanent tissues are derived from meristematic tissue once they lose theability to divide.

3. Parenchyma tissue is a type of permanent tissue that consists of relativelyunspecialised cells with thin cell walls.

4. Xylem transports food from leaves to other parts of the plant.

5. Stomata present in the epidermis of the leaf are necessary for the exchange ofgases with the atmosphere.

6. Parenchyma are permanent live cells with thin cell walls.

7. Collenchymatous tissue consists of long and narrow dead cells with thick cellwall due to lignin.

FA 2.4: Concept-based Worksheet

'N is a permanent (plant) tissue with following characteristics:

1. It consists of relatively unspecalised cells with thin cell walls.2. It is live, usually loosely packed.

3. It provides support to the plant and also stores food.

Identify 'N and answer the following questions.

(a) Write different types of 'A: tissue.(b) Name the following:

(i) Tissue that contains chlorophyll and performs photosynthesis

(ii) Tissue with large air cavities that provide buoyancy to the plant(iii) Tissue that allows easy bending of various plant parts'without breaking

(iv) Husk ofa coconut is made of which tissue?

FA 2.5: Diagram-based Worksheet

Identify and name the following tissues.

(a) (b)

•

(c)

Tissues 57

FA 2.6 Group Discussion

Divide the class in small groups. Discuss various plant tissues among each group.Now, on the basis ofyour discussion, discuss the following questions in your groups.

1. Where is meristematic tissue found in plants?

2. What are the various types of tissues in plants?3. What is the difference between parenchyma and collenchyma tissues?

4. Write the difference between xylem and pWoem.

5. Name the different components of xylem and phloem.

Animal Tissues

Breathing is one of the most vital activities of humans. When we breathe wecan feel the movement of the chest. How do these body organs move? For thisyou have specialised cells in your body called muscles cells. The contraction andrelaxation of these cells result in movement of your chest. During breathing youinhale 02. Where does this O2go? It goes to our lungs and then is transported to allthe body cells through blood. Can you think why would cells need 02?

You studied about mitochondria in the earlier chapter which is present ineach and every cell of your body. They utilised O2 and released energy in the formof ATP molecule. These ATP molecules provide energy to all work performed byour body cells. Blood is also a fluid connective tissue. It follows and carries varioussubstances from one part of the body to the other. For example, it carries 02 andfood to all cells. Blood also collects wastes from all parts of the body and carries themto the liver or kidneys for removal. Thus, muscles and blood, both are examplesof tissues. There are four major types of tissues on the basis of their functions inmulticellular animals, including man.

(1) Epithelial tissue: Protective and covering tissue.

(2) Muscular tissue: Contracting and relaxing tissues carryIng movements ofvanous organs.

(3) Connective tissue: Connecting, packing and supporting tissues.

(4) Nervous tissue: Conducting impulses between central nervous system (brainand spinal cord) and other organs.

These tissues are further differentiated as shown below:

b. Cuboidal(Cubelike)

(ii) Lymph

Tissues

d. Fluid

4. Nervous

(i) Blood

C. Skeletal

(i) Cartilage (il) Bone

3. Connective

b.Adipose

c. Cardiac(Heart

muscle)

(ii) Ugarnent

a. Areolar

b. Unstriated(Visceralmuscle)

(i) Tendon

Animal Tissues

2. Muscular

a. Striatede. Glandular(Secretory)

d. Ciliated

C. Columnar(Tall)

58

a. Squamous(Flattened)

1. Epithelial

.~ •.-----

(b) Cuboidal epithelium(d) Ciliated epithelium

Epithelial Tissue or Epithelium (Epi =upon, thelio = to grow)It is the simplest tissue. This tissue covers the entire body externally as well as

'TTlally. It is the protective tissue of the animal body. The cells of the tissue are~_t1y packed and form a continuous sheet. These are without intracellular spaces

intracellular matrix. These rest upon a non-cellular layer known as basementmbrane which contains a special form of matrix protein, called collagen.,ithelium covers most organs and cavities within the body. It also forms a barrierkeep different body systems separate. The skin, the lining of mouth, the liningblood vessels, lungs, alveoli and kidney tubules are all made of epithelial tissue.

_pithelial tissue may be simple, i.e., composed of a single layer or stratified, i.e.,de up of several layers of cells.

clions

(i) The entire body is covered by epidermis (outermost layer of skin), whichprotects the body from drying, injury and chemical effects and infections.

(ii) Some epithelial cells secrete enzymes and hormones (e.g., glandularepithelium).

(iii) Certain epithelial cells filter waste products from the blood such as urine,sweat and carbon dioxide.

(iv) Epithelial cells absorb water and nutrients in the intestine (e.g., columnarepithelium).

(v) Certain epithelial cells receive various stimuli, e.g., olfactory epithelium,epithelium of internal ear.

(vi) Certain epithelial cells secrete mucous which lubricate the surface ofthe epithelium.

Types of simple epithelial tissue: On the basis of shape and functions of cells,epithelial tissue is classified as follows:

(a) Squamous epithelium

(c) Columnar epithelium

(e) Glandular epithelium

I (a) Squamous Epithelium

Nature: It is composed of a single layer of thin and flat, plate-like cells. Theyare united with each other to form a sheet. These cells form a sheet-like structurewith mosaic appearance.

Occurrence: It is found on the surface of skin, e.g., (epidermis), lining of bodycavities like mouth, oesophagus, lining ofblood and lymph vessels, ducts ofglands, etc.

Functions

(i) It protects the underlying parts of the organ from injury, drying, entry ofgerms, etc.

(ii) These epithelia serve for easy exchange of materials by diffusion acrossthem, for instance, in blood vessels and alveoli.

Free surface

~.~;;Basement membrane

FIg. 2.18 Squamous epithelium

Tissues

Q~~~~~~~~~~-,Stratum/ spinosum

c:~-- Stratumbasale

Keratinised Stratified Squamous Epithelium

It is found in the skin and covers the external dry surfaceof the skin. It consists of several layers of cells. The cells of thedeepest layer are cuboidal but those of the outer or surface layervary in nature. In the outer few layers, the cells become hard anddeposit a waterproof keratin or corny substance. This is calledkeratinisation or cornification. These layers consist of flat, deadcells and are referred as stratum corneum or horny layer (seeFig. 2.19).

It is shed at intervals due to friction as small pieces. It formsthe epidermis of the skin in terrestrial vertebrates. It prevents lossof water and mechanical injury.

F~219

Fig. 2.20 Cuboidal epithehum

NucleusI (b) Cuboidal Epithelium

Nature: Its cells are cube-shaped, isodiametric and closely fittedtogether. They appear square-shaped in section and their free surfaceappears to be hexagonal.

Occurrence: It is found in some parts of kidney tubules andducts of salivary glands, thyroid gland, sweat gland and exocrineglands like pancreas. It also forms the ovaries and lines thegerm-producing tubules of the testis, here, it is known as germinalepithelium.

Functions:(i) It helps in absorption, secretion and excretion.

(ii) It provides mechanical support.

Cytoplasm

Cementsubstance

••

Basementmembrane

Fig. 2.21 Columnar epithelium

Columnar cell

Basementmembrane

Nucleus I (c) Columnar Epithelium

Nature: This epithelium consists of cells which are much longer thanbroad (i.e., pillar like). Nuclei are placed near the base at the samelevel. Often their free borders bear microvilli.

Occurrence: It forms the lining of the alimentary canal from stomachto rectum, gall bladder, bronchioles of lungs, uterine tube and uterus.Functions: It helps in absorption ofnutrients in stomach and intestine,and secretion of mucous from mucous secretory glands. called gobletglands.

Columnar cell

F.g 222 C a ec columnar epithelium

Cilia

/Basement ..membrane

NucleusI (d) Ciliated Epithelium

Nature: It consists of columnar or cubical cells, has numerous, thin,delicate, hair like projections called cilia arising from the outer freesurface of the cells.

Occurrence: This is found in the trachea (wind pipe), bronchi (inlungs) and bronchioles (branches of wind pipe), kidney tubules, spermducts and fallopian tubes (oviducts).Functions: Cilia beat only in one direction and thus, expel mucus anddust, etc., from the lungs to the exterior. Similarly sperms and ovadescend downward.

60 Issues

Gobletcell

Mucous-secreting'goblet' cell

~

\. ........ J

a~M~'Fig. 223 Glandular epithelium

showing goblet cells in intestine

illIIColumnar-----, ,

I (e) Glandular Epithelium

Some ofthe columnar epithelial cells of the epithelium change into glandularcells. Often a portion of the epithelial tissue folds inward and a multicellulargland is formed. This is glandular epithelium. It is found in the skin, lining ofalimentary canal, pancreas, etc., secreting mucous, enzymes and hormones.Their main function is secretion.

Remember

Epithelial tissue is found on the body surface and the covering of externaland internal surface of organs. Epithelial cells are closely placed with each otherand also placed on non-cellular basement membrane. Their function is protection,absorption, secretion and excretion.

Ciliated epithelium is found in trachea, bronchi and bronchioles, kidneytubules, sperm ducts and fallopian tube.

Glandular epithelium is found in glands.

2. Muscle Tissues (or Muscular Tissues)

The movement of internal organ such as heart and alimentary canal arecaused by these tissues. Muscle cells are typically arranged in parallel arrangementallowing them to work together effectively. Muscles are responsible for all outwardmanifestations of life. The muscular tissue is formed of greatly elongated and ltighlycontractile tissues and muscles cells which are called muscle fibres. These are placedtogether in the connective tissue to form bundles.

Functions

(a) Striated Muscles

Sarcoplasm

Nucleus

Sarcolemma

61

Fig. 2.25 Striated muscle fibre

Darkbands

Myofibn

Each striated muscle cell or fibre is long cylindrical, non-tapering,nbranched and multinucleated (having many nuclei), It consists ofthin outer limiting membrane, called sarcolemma, which enclosescoenocytic plasma, known as sarcoplasm. The nuclei are manyd peripheral. In the sarcoplasm (cytoplasm) of the muscle cell arebedded a large number of contractile elements, called mYofibrils or

rcostyles running parallel to one another lengthwise,

:i...les

These muscles are also known as striped, skeletal or voluntary muscles.

Nature: These muscle fibres or cells show transverse dark and'.ght striations or bands due to which these are called striated or striped

uscles. Since these muscles are attached to the bones in different partsf the body and hence are responsible for body movement, they are

'Ca1Ied skeletal muscles. These muscles work according to our will; theye also called \'oluntan muscles.

(i) Movement of organ(ii) Locomotion

(iii) Opening and closing of apertures

(iv) Increasing and decreasing size of cavities or lumen of hollow organs

(v) Providing the proper shape of the body(vi) Beating of heart

Muscles are classified into (a) striated muscles (skeletal muscles), (b) unstriatedmuscles (smooth muscles) and (e) cardiac muscles.

Functions(i) The unstriated muscles are never under the control of our will, hence, they

are also known as involuntary muscles. Movement of food in the alimentarycanal or opening and closing of cavity are involuntary movements.

(ii) These are independent of voluntary control except the ciliary muscle of theeye.

(iii) They show slow and sustained contraction and relaxation (i.e., peristalticmovements which push the food onward) movements in the intestine.

Occurrence: These are found in muscles of limbs (e.g., bicep and tricep'muscle of arms) in the form of bundles. These are also present in the abdominalwall in the form of sheets, diaphragm, tongue, pharynx and these are called yiscerastriated muscles since these are found in internal (visceral) organs.

Functions

(i) These muscles are strong and powerful and undergo rapid contraction andexpansion. These muscles become tired due to continuous use for a long timeand so they need rest.

(ii) These muscles provide force for locomotion and all other voluntarymovements of the body parts.

Occurrence: These are found in the wall of visceral organs exceptthat of heart, that is why they are called visceral muscles:

Thus, they occur in this wall of stomach, intestine and rectum, wallsof arteries and veins, urinary and genital ducts, bronchioles, muscles ofiris and ciliary body, etc.

Nature: These are also called smooth, yisceral or involuntary muscles. Thecell structure is relatively simple. The cells or fibres are elongated and spindleshaped (pointed at both ends). These are held together by loose connective tissues.Each muscle cell is enclosed in a delicate and transparent plasma membrane. Itconsists of a long cigar-shaped nucleus in the centre of cytoplasm or sarcoplasm.

The sarcoplasm contains fine longitudinal contractile thread calledmyofibrils. The fibres have no striations or bands across muscles hence,are called smooth or unstriated muscles.

I (b) Unstriated Muscles

Nucleus Spindle shaped/\ ;;:Cle ce~s:a ;& ~s-=~--

- ==-===-Fig, 2.26 Smooth muscle cells (fibres)

-.... =-.=

Fig. 2.27 Cardiac muscles

I (e) Cardiac MusclesNature: These muscles resemble striated muscles but, functioning independendy

of the conscious control of brain, these are involuntary like the smooth muscles.Cardiac muscles are composed of branched fibres, the branches join to form anetwork (see Fig. 2.27). Each fibre is surrounded by very thin sarcolemma and hascytoplasm (sarcoplasm) with longitudinal myofibrils and centrally located nucleus(i.e., each cell is uninucleated). The intracellular spaces of cardiac muscles are

filled with abundant loose connective tissues richly supplied with bloodcapillaries.

The fibres are joined end-to-end and are interconnected by obliquebridges. The ends of these fibres have zig-zagjunctions, called intercalateddisc. These act as boosters for the wave of muscle contractions. These areregions of interdigitation of sarcolemmas of adjacent muscles or fibres(i.e., each fibre of cardiac muscles is formed due to joining of individualuninucleated muscle cells to one another in a linear arrangement).

Occurrence: These muscles are present in the walls of heart.

Space between fibresfilled with capillariesand connectIVe tissue

MyofibrisIntercalated

disk

VK Biology IX 62 Tissues

Functions

(i) Cardiac muscles contract and relax rhythmically throughout life withoutshowing any fatigue.

(ii) Rhythmic contraction and relaxation of cardiac muscles maintain the flow ofblood in the heart and blood vessels.

Table 2.5 Comparison of Muscular Tissues

S.No. Striated Muscles Unstriated Muscles Cardiac Muscles

J. Voluntary or skeletal. lnvoluntary, smooth or Heart.plain.

2. Sarcolemma present. Sarcolemma delicate and Sarcolemma present.transparent.

3. Myofibrils in sarcoplasm Myofibrils indistinct and Myofibrils distinct anddistinct and cross not cross striated. faintly striated.striated.

4. Fibres or cells Unbranched. Fibres branched.unbranched.

5. Nucleus, many in each Single nueleus. Single nueleus.cell.

6. Intercalated discs absent. Intercalated discs absent. Intercalated discspresent.

7. Contraction rapid Contraction slow and Contraction moderatepowerful. rhythmic. and rhythmic.

3. Connective Tissue

Fibroblast

Collage'n fibre Mast cell Plasma

FIg_ 2.28 Areolar connective tissue

Reticular fibre

(b) Adipose tissue;(d) Skeletal tissue;

Nature: It is also known as loose fibrous connective tissue orspongy fibrous tissue. It consists of a transparent jelly-like stickymatrix having different types of cells and fibres and lot of mucin.

Its matrix consists of two types of fibres.

(i) White collagen fibres that change into gelatin on boiling inwater.

(ii) Yellow elastic fibres: Also scattered in matrix are severalkinds of irregular cells (e.g., fibroblast). Some of these canengulf bacteria and prevent infection.

I (a) Areolar (or Loose) Connective Tissue

The name connective tissue is derived from its property to connect and binddifferent tissues or organs. It also provides the structural framework and mechanicalsupport to the body. It also plays a role in body defence. tissue repair, fat storage,etc. It is composed of two basic components, namely, cells and their surroundingextracellular matrix. The cells are loosely arranged and lie embedded in the matrix,which consist of protein fibres, amorphous ground substance and tissue fluid.The matrix may be jelly like, fluid, dense Or rigid. The nature of matrix differs inconcordance with the function of particular connective tissue.

Types of connective tissue: In animals, connective tissue is of the followingtypes:

(a) Areolar (or loose) connective tissue;

(e) Dense regular connective tissue;

(e) Fluid connective tissue.

Tissues 63 VK Biology IX

~~~----------------------_.--_....._--------_.~----..

Occurrence: Areolar tissues are the most typical types of connective tissues,having a very widespread distribution. These tissues are found between the skinand muscles, around blood vessels and nerves and in the bone marrow.

Functions

(i) It gives support to various organs and acts as a packing material betweenvarious structures of the body. utritional exchanges occur through matrix.

(ii) Injured tissues are repaired by the fibroblasts by producing collagen fibres.

(iii) It defends the body against bacteria, microorganisms and other foreign bodies.

I (b) Adipose Tissue (Fatty tissue)

Nature: It is a modified form of connective tissue. The fibres in adipose tissueare scanty. The matrix of adipose tissue is packed with large, spherical or oval fatcells or adipocqes. These store fat in the form of a large fat globule, which squeezethe cytoplasm to the periphery and nucleus to one side.

Occurrence: The adipose tissues are present beneath the skin, around kidneysand in mesentry and bone marrow.

Nucleus Functions

Fig. 2.29 Adipose tissue

(i) It forms soft elastic pads between organs and parts. It maintains thekidney, its position and eye balls in the bony orbits and forms shockabsorbing cushions around both.

(ii) It acts as a shock absorber, found beneath the skin, sole of foot andin the palm.

(iii) It stores fat.

(iv) It also gives shape to the body and hmbs.

(v) It prevents the loss of body heat, thus, acts as an insulating blanket.Thus, it regulates the body temperature.

I (c) Dense Regular Connective Tissue

--'-''-----'---- Ligament

J-~~----Bone

Muscle

Tendon

Fig. 2.31 Attachment of tendons and ligaments

Nature: Dense regular connective tissue is a fibrous connective tissue. It ischaracterised by ordered and densely packed collection of fibres and cells. It is theprincipal component of tendons and hgaments.

(i) Tendons: It is a dense, strong fibrous connective tissue with thick parallelbundles of collagen fibres (matrix). It has cord-like strong inelastic structure.It connects muscles to bones. It has great strength but limited flexibility. Thecollagen fibres are present in rows of fibroblast and are bounded by areolarconnecting tissues.

(ii) Ligaments: It is also a densefibrous connective tissue. Itsground substance or matrix isdensely crowded with yellowelastin fibres branched mdifferent directions. A fewelongated fIat cells (fibroblasts)lie scattered between the fibres.The ligament connects bonesat the joints arid hold them inposition-thus, enables us tomove and rotate our neck, limbs,fingers, etc., comfortably.

Fig. 2.30 Dense regularconnective tissue

~tit:=::~E: Fibroblastsf Collagen

fibres

64 Tissues

Table 2.6 Comparison of Tendons and Ligaments

S.No. Tendons Ligaments

1. It is a thick, tough and non-elastic It is a strong but elastic bond of connectiveconnective tissue. tissue.

2. It connects muscles to a bone. It connects two bones.

3. It is formed of wrute fibrous tissues. It is formed ofyellow elastic fibrous tissues.

4. Fibres are white and formed of Fibres are yellow and formed of proteincollagen protein. elastin.

5. It helps in movement ofbone. It restricts or limits the movement ofbones.

(d) Skeletal Tissue

The skeletal tissue forms a strong framework. It supports the body, protectsvital organs and provides hard surface for the insertion of muscles. It occurs intwo forms: Cartilage and bone.

c~hndrocyte

~Hyaline ~/'malnx ~ y

Fig. 232 Hyaline cartilage

Fig. 2.33 Section of cartilage

.•'':"""''''.S

Perichondrium

IChondrrlaSI

~_1Lacunae---.;J~:,'-~

.;;\~

(1) Cartilage

Nature: It is solid but semi-rigid and flexible connective tissue.The matrix of cartilage is called chondrion. It is tough, transparentand homogeneous, formed of a special glycoprotein chindromucoid.It is secreted by cartilage cells or condrocytes. These are enclosed influid filled spaces, called lacunae. The cartilage is bounded externallyby white fibrous connective tissue perichondrium. The blood vesselsare present in the perichondrium but not the matrix. The food andoxygen diffuse through matrix to reach the condrocytes. The cartilageincrease in size by the addition of new layers of matrix below theperichondrium, by the division ofchondrocytes (intestitial growth) andby the addition of chondroblasts from the perichondrial fibroblasts.

Occurrence: Cartilage is found in nose tips, ear pinna, ring of trachea (windpipe), end of long bones, lower ends of ribs, and epiglottis.

Function: It provides support and flexibility to the vertebrate body parts.

-VK Biology IX '

l~jJncanal

\'~~LFig. 234 Compact bone

Nucleus

ProtoplasmProcess

Osteoblast

Canaliculi

Transverse section of bone Single bone-secreting osteoblast

Fig. 235 SeclJon of bone (a part)

~ Lacunae

(2) Bone

Nature: Bone is a solid, rigid and strong connective tissue. Its matrix is hardbeing formed of ossein. Matrix of bone is rich in phosphate, sulphate, carbonate andfluoride salts of calcium and magnesium. The bone cells are called osteocytes. Theseare stellate cells and each of them is enclosed in a small cavity, the lacuna. These areconnected together by several fine and branched canaliculi. Fine processes ofosteocytesextend through these conaliculi and are connected with the processes ofother osteocytes.

-=Haversiancanal

~~~~~~ Bone"" AlOOlL....<J/I lamellae

Tissues 65

....

Functions

(i) It forms the framework that supports the body.

(ii) It protects vital body organs like brain, lungs, etc.

(iii) It anchors the muscles.

(iv) It provides shape to the body.

Table 2.7 Difference between Cartilage and Bone

S.No.

I.

Cartilage

Matrix is composed ofa firm, but flexiblematerial, called chondrion.

Bone

Matrix is composed of tough inflexiblematerial, called ossein.

2. Cartilage is surrounded by a firm sheath Bone is surrounded by a tough sheath,called perichondrium. called periosteum.

3. Blood vessels absent. Blood vessels present.

VK Biology IX

4. Cartilage cells (choridroucytes) lie singly Bone cells (osteocytes) lie in lacunaeor in groups of two or four. singly.

5. Chondrocytes are oval and devoid of Osteocytes are irregular and gIve offprocesses. branching processes.

I (e) Fluid Connective Tissue

It is also called vascular tissue and is a special connective tissue that differsfrom a typical connective tissue in the following respects:

(i) The matrix is in the form of a fluid and fibre free.

(ii) Matrix is not secreted by the cells.

(iii) The cells lack power of division.

Vascular tissue circulates in the body and helps in the transportation ofmaterials from one part of the body to other part. It also plays an important role inthe defence mechanism of the body.

Types of Vascular Tissue

Vascular tissues are of two types: (a) Blood and (b) Lymph.

(A) Blood

Blood is a fluid connective tissue. It is salty in taste and slightly alkaline innature. In human beings, it forms 7-8% ofthe body weight (about 5litres). Blood isa complex transport medium. It performs vital pick up and delivery services for thebody. It contains two components:

(I) Plasma and

(2) Blood cells (corpuscles)

(I) Plasma: It is a straw-coloured fluid, and makes up about 60% of the totalblood volume or about 5.0% of the body weight. Plasma is a complex fluidand includes in it inorganic salts and organic compounds. Organic substancesof plasma are soluble. Proteins like albumins (which maintain the pressure ofblood); Globulin (some act as antibodies); and fibrinogen (blood clotting); andglucose, amino acids, lipids, vitamins, enzymes, hormones, etc. Supply bloodto all cells of the body and waste materials (urea, uric acid) are transported tokidneys for excretion.

(2) Blood Cells: It is of three types:(i) Red Blood Cells (RBCs) or erythrocytes

(ii) White Blood Cells (WBCs) or leucocytes

(iii) Platelets(i) Red Blood Corpuscles (RBCs): The unique feature of RBCs is the

presence of a red, oxygen-carrying pigment, the haemoglobin, in theircytoplasm. The shape and size of RBCs vary in different animals. Thecells may be uninucleated or non-nucleated. In almost all the vertebrates,except mammals, these are nucleated, oval and biconvex. In mammalsthese are non-nucleated, bioconcave and circular. Actually, the nucleus ispresent in the RBCs of mammals initially but when these cells are finallydifferentiated and mature, the nucleus, mitochondria and endoplasmicreticululTI are degenerated. Such cells accommodate more haemoglobinfor transportation of 02'

(ii) White Blood Cells (WBCs): These are colourless, nucleated and motile(amoeboid) cells of blood, much larger than RBCs, but less in number.All leucocytes are capable of amoeboid movement. These are of twomain kinds; phagocytes and immunocytes. Phagocytes are capable ofphagocytosis and they carry out the function of body defence by engulfingbacteria and other foreign substances. These are of two types:

(a) Granulocytes: They have irregular-shaped nuclei and cytoplasmicgranules with specific staining properties. They include eosinophils,basophils and neutrophils.

(b) Agranulocytes: These are nongranular leucocytes, having a roughlyround or indented nucleus and clear cytoplasm. They includemonocytes. They ultimately migrate to body tissue and transform intomacrophages and histocytes,

(c) Immunocytes: They produce antibodies and are involved in immuneresponse. They include lymphocytes that contain central, sphericalnucleus and a little cytoplasm with no granules and produce antibodies.

(iii) Blood platelets or thrombocytes: These are minute, highly contractile,round or oval, biconvex discs with granular cytoplasm, but without nucleus.As is recently discovered, the platelets are fragments which form as budsand pinch off from certain large cells (megakaryocytes) in bone marrow.They help in the clotting of blood in the site of injury to a blood vessel, soas to prevent further loss of blood.

Occurrence: It occurs in blood vessels called arteries, veins and capillariesthat are connected together to form the circulatory system. The highly branchingnetwork of vessels enables blood to reach every part of the body.

Functions: Blood is an important tissue since it performs many importantfunctions in the body.

(i) It transports oxygen from respiratory organs to various body tissues.

(ii) It carries carbon dioxide from body tissues to respiratory surfaces like lungs,skin, etc.

(iii) Digested food absorbed from the intestine is carried to different parts of thebody.

(iv) It carries excretory wastes produced in the body to kidneys for elimination.

(v) It maintains the body temperature.

67

(B) Lymph

Nature: It is also a fluid connective tissue flowing in definite lymph vessels.Lymph is colourless since it has no red blood cells, but it contains more WBCs thanthe blood has. It also contains glucose, amino acids, vitamins, salts and urea.

Functions

(i) It transports the nutrients (02 and glucose) which may have filtered out ofthe blood capillaries back into the heart to be recirculated in the body but hasfailed to return into various capillaries.

(ii) The WBCs of the lymph are the same as those of blood and have the samefunction of defence and of assistance in tissue repair and healing.

(iii) It brings carbon dioxide and nitrogenous wastes from tissue fluid to blood.

Table 2.8 Comparison of Blood and Lymph

S.No. Blood

1. Red cells present.

2. Amount of nutrients and 02comparatively more.

3. Amount of CO2 and metabolic wastesless.

4. White cells fewer.

5. Nutrophils most numerous.

6. Soluble proteins more than insolubleproteins.

4. Nervous Tissue

Lymph

These are absent.

Amount of nutrients and O 2comparatively less.

Amount of these wastes are much more.

White cells more.

Lymphocytes most numerous.

Insoluble proteins more than solubleproteins.

Dendrites

~'-~Nucleus

., Myelin sheath

Axon/

Terminal branches

Fig. 2.36 ANeuron

Nature: A tissue which is specialised for receiving and transmitting messagesin our body is nervous tissue. The brain, spinal cord and nerves are all formed ofnervous tissues. The nervous tissue is composed of specialised cells or neurons, whichreceive the stimuli from within and outside the body and send impulses (signals) tovarious parts of the body. The signals or impulses travel from one neuron to the other.

I Structure of Neuron

A neuron or nerve cell consists of three parts (Fig. 2.36):

(a) Cell body or cyton is bounded by a thin cell membrane, enclosing the cytoplasm,called neuroplasm. A large central nucleus is found in the neuroplasm.

(b) Dendrons or dendrites are short processes arising from the cyton. Theyconduct impulses into the cyton from the receptor organs.

(e) Axon is single, thick and large. It arises from the cyton and terminally it isbranched. Axon is also known as nen'e fibre. Axons carry nerve impulses awayfrom the cyton, i.e., to effector organs (muscles).

Function

Dendrons of the nerve cell receive impulses from receptor organs, carry to thecyton and axon transmits them away from the cyton to another neuron or effectororgan.

68 Tissues

FORMATIVE ASSESSMENTFA 2.7 Diagram-based Worksheet

Study the diagram and answer the questions that follow.

A.

3

I. Complete the diagram by drawing the missing parts.2. Identify the parts numbered 1,2 and 3.

4. What is the term given to the gap between two nerve cells?

5. Name the part of the neuron from which the nerve impulse is transferred tothe second neurons.

B. Given below are the pictures of different types of epithelial tissues. Mentionthe name of correct epithelial tissue under their respective pictures.

.. '

FA 2.8 Mapping-type Worksheet

Complete the following map.

Tissues 69

.,

70

FA 2.9: Match the following

Match the terms given in column I to their meanings in column II.

Column I Column I

(a) Blood (i) Smoothens bone surfaces at joints

(b) Involuntary movements (ii) Fluid connective tissue

(c) Cartilage (iii) Movement of food in alimentarycanal or contraction and relaxationof blood vessels

(d) Cuboidal epithelium (iv) Forms oesophagus and the liningof the mouth

(e) Columnar epithelium (v) Forms the lining of kidney tubulesand ducts of salivary glands

(j) Simple squamous epithelium (vi) Forms the Inner lining of theintestine

FA 2.10 True or False


l. A neuron consists of a cell body with a nucleus and cytoplasm from which longthin hair-like parts arise.

2. The movements of food in the alimentary canal or the contraction andrelaxation of blood vessels are involuntary movements.

3. The areolar connective tissue is found in the nose, ear, trachea and larynx.

4. Bone is a connective tissue which forms the framework that supports the body.5. In the respiratory tract, the cuboidal epithelium tissue also has cilia, which are

hair-like projections on the outer surfaces of epithelial cells.

6. The skin lining of the mouth, lining of blood vessels, lung alveoli and kidneytubules are all made of connective tissue.

7. Muscular tissue consists of striated, unstriated and cardiac tissues.

8. The muscles of the heart showing rhythmic contraction and relaxation arecalled cardiac muscles.

FA 2.11: If I was A ... ? Worksheet

Pretend that you are an animal tissue for the remaining questions.

l. Name the different types of tissues found in you.

2. Name the tissue which is found on the surface of yOUT skin and is composed ofa single layer of thin and flat, plate-like cells.

3. Where is cuboidal epithelium found in yOUT body?

4. Which ofyour connective tissues helps in forming the framework that supportsthe body?

5. What are the functions of voluntary and involuntary muscles in yOUT body?6. Which of your tissues transmits stimulus very rapidly within the body? Name

the parts composed of such tissues.

Tissues

SUMMARY

I Epithelial tissue covers the external and internal surfaces of the body and variousorgans.

I Epidermis of skin is formed of stratified epithelium.

I Glands are formed of glandular epithelium secreting mucous and enzymes, etc.

I Goblet cells are glandular epithelial cells that secrete mucous.

I Areolar or loose connective tissue is formed of various types of cells, unbranchedcollagen and branched elastin fibres scattered in a large intercellular space or matrix.

I Cells are fibroblasts secreting fibres, macrophages or histiocytes engulfing bacteria,etc., mast cells secreting heparin, histamine and serotonin, adipose cells storing fat,etc.

I Adipose cells store fat in their vacuoles and also have fibres in between cells. Denseconnective tissue forms ligaments and tendons.

I Tendons are formed of collagen fibres and in between them are fibroblasts. Tendonsconnect muscles to bones.

I Ligaments have collagen and elastin fibres and squeezed fibroblasts. They connectbone to bone. Striated muscle fibres have cross-striated myofilaments in sarcoplasm.Each fibre is multinucleated. Non-striated muscle fibres have no cross bandedmyofilaments. Each fibre has a single nucleus.

I Cardiac muscle fibre is uninucleated and branched. Myofilaments have faint crossstriations.

I Sarcoplasm is the cytoplasm of muscle fibres.

I Sarcolemma is the limiting membrane of muscle fibre.

I Intercalated disc is the thick transverse band between two adjacent cardiac cells.

I Myofilaments are present in the muscle fibres in sarcoplasm. In striated muscle fibresthick and thin myofilaments are present.

I Cyton is the cell body of neuron or nerve cell.

I Dendrons or dendrites are short processes of cyton.

I Axon is a single long process of cyton.

I Synapse is the junction or union between the branches of two neurons.

I Tissue is a group of cells of common origin, having similar structure and function.

I Plant tissues are of two types: meristematic and permanent.

I 1. Meristematic tissues are present in growing regions of plants. Its cells continuouslymultiply so that the region grows in length and breadth. This tissue is of three types:

(i) Apical meristem found at the apex of shoots and roots. Root tip is covered by rootcap.

(ii) Lateral meristem is found on lateral sides of stem and root, e.g., cork cambium andcambium of vascular bundles.

(iii) Intercalary meristem is a part of apical meristem which separates off laterally fromthe apical meristem.

I 2. Permanent tissues arise from meristematic tissues, cells of which after maturityform permanent tissues. It is of two types: simple tissues and complex tissues.Simple tissues are of three types:

(i) Parenchyma cells are living and cytoplasm is vacuolated and possess intercellularspaces, cell wall is thin.

(ii) Collenchyma cells are living and contain chloroplasts. Hence, they are capable of

Tissues 71

72

synthesising starch and sugar. Being elastic, it gives tensile strengths to the stem.No intercellular spaces.

(iii) Sclerenchyma fibres or cells are long, narrow and pointed. On maturity, protoplasmdries off. Sclereids or stone cells or grit cells are of irregular shape. Cells lumen isnarrow and gives strong support to the stem.

I Protective tissues are epidermis of leaves possessing stomata for exchange of gases.Cork is found on the outermost side of stem. Its cells are dead.

I Complex tissues are xylem and phloem. Xylem forms the woody part of stem. Xylemand phloem forms the vascular bundle. Xylem is constituted by four types of cells (e.g.,sclereids, tracheae and xylem fibre or sclerenchyma are dead and xylem parenchymais living) and it conducts water and nutrients from soil through roots to the leaves.

I Phloem is also formed of 4 types of cells: sieve tubes, companion cells, phloem fibresand phloem parenchyma. Sieve tubes and companion cells transport manufacturedfood from leaves to other parts of plants. Phloem fibres and sieve tubes are dead.

I Animal tissues include epithelial, connective, muscular and nervous tissues.

I Epithelial tissue is found on the surface of the body and various organs, lining thecavities of tubular organs. Its cells are of various shapes and are held together witha small amount of intercellular substance, matrix. Epithelium is of two types: simpleformed of a single layer of cells and stratified formed of a number of cell layers.

I Simple epithelial is squamous, cubOidal, columnar, glandular and ciliated.

I Stratified epithelium cells are arranged in layers, like epidermis of skin.

I Muscular tissue includes striped, unstriped and cardiac muscles. Their cells or fibresare long and nucleated.

I Striped muscle fibres or cells are multinucleated and show alternate dark and lightbands, due to which they are called striped. Muscles of legs and hands are of stripedtype. Each muscle fibre contains a number of thin and thick myofilaments withinsarcoplasm.

I Non-striped or visceral muscle fibres are also long, cylindrical and uninucleated. Eachfibre also contains numerous lengthwise arranged myofilaments in sarcoplasm. Thesemuscles are found in the walls of internal organs of the body.

I Cardiac muscle fibres or cells are branched and uninucleated. The sarcoplasm of thesecells also contains myofilaments showing faint cross striations. Branch of a cell joinsthe branch of adjoining cell. At the junction of adjacent cell is present a transverseintercalated disc. In between adjacent cells are present intercellular spaces havingloose connective tissue. It is found in heart due to which it contracts rhythmically.

I Connective tissue connects and anchors various organs of the body and gives supportto the organs. It contains an abundant jelly-like intercellular medium (matrix), fibres(white and yellow) and various types of cells, e.g., fibroblasts, macrophages, mastcells, adipose cells and immunocytes.

I Connective tissues are areolar (loose), dense and adipose tissues.

I Tendons join muscles to bones and ligaments join bone to bone, and both are denseconnective tissues.

I Adipose tissue cells store fat globules. Cytoplasm with nucleus is peripheral.

I Blood and lymph are fluid connective tissues. Lymph is colourless and has plasma minusred blood cells and certain proteins. Cartilages and bones are skeletal connective tissues.

I Nervous tissue is formed of neurons. A neuron has a cell body, the cyton, a few smallbranches of cyton, the dendrons or dendrites and a single long branch is called axon.

I Axon carries away impulses from cyton and transmits them to another, whereasdendrons receive impulses and transmit them to cyton.

Tissues

FORMATIVE ASSESSMENT FOR PRACTICEFA 1. Wordplay

A wordplay is one where you choose a word or name and use each letter in the name as thebeginning of a word or line that says something about that person or topic.

Example: As given in Chapter 1.

Write the wordplay using the word below:

p-----------------------------A _

R _

E _

c _H _

y-----------------------------M _

A _

FA 2. Young Scientist

Jar B

LJar A

To show how apical meristem increases length of the stem and the root

You will need: Two glass jars, water, two onion bulbs, scissors andrecord book.

• Take two glass jars, fill bOlh oflimn wilh waler.

• Label one as ll' and another as 'B'. Now, take two onion bulbs and place them ontlze mouth ofjar.

• Observe the growtlz of the roots in both tlze jan, i.e., ll' and 'B', for few days.

• Measu1"f tlze length of roots on day 1, day 2 and day 3 in both tlze jars.

• Document your observation in your notebook.

• On day 4, take out the onion bulb fmmjm' 'B' and cut tlze Toot tips.

• Now, again observe the gmwtlz of TOOts in botlz tlze jars, i.e., ll' and 'B'.

• Afterfew days observe tlze changes and document Jour observations.

Results

From the above observation, fiU in the blanks:

Jar has longer roots because _

Tissues 73

(ii) Smooth muscles(iv) Skeletal muscles

(b) (ii) and (iii)

(d) (i) and (iv)

(b) ear

(d) larynx

(b) Caseous exchange

(d) Transpiration

FA 3. Multiple Choice QuestionsSelect the right choice

1. Which of the following tissues has dead cells?

(a) Parenchyma (b) Sclerenchyma

(c) Collenchyma (d) Epithelial tissue2. Girth of stem increases due to

(a) apical meristem (b) lateral meristem(c) intercalary meristem (d) vertical meristem

3. A person met with an accident in which two long bones of hand were dislocated. Whichamong the following may be the possible reason?

(a) Tendon break (b) Break of skeletal muscle(c) Ligament break (d) Areolar tissue break

4. While doing work and running, you move your organs like hands, legs, etc. Which amongthe following is correct?

(a) Smooth muscles contract and pull the ligament to move the bones

(b) Smooth muscles contract and pull the tendons to move the bones(c) Skeletal muscles contract and pull the ligament to move the bones

(d) Skeletal muscles contract and pull the tendon to move the bones

5. Which muscles act involuntarily?(i) Striated muscles

(iii) Cardiac muscles(a) (i) and (ii)

(c) (iii) and (iv)

6. Which is not a function of epidermis?

(a) Protection from adverse condition

(c) Conduction of water7. Select the incorrect sentence

(a) Blood has matrix containing proteins, salts and hormones(b) Two bones are connected with ligament

(c) Tendons are non-fibrous tissue and fragile

(d) Cartiage is a form of connective tissue8. Cartilage is not found in

(a) nose(c) kidney

9. Bone matrix is rich in

(a) fluoride and calcium

(c) calcium and potassium10. Contractile proteins are found in

(a) bones

(c) muscles11. Nervous tissue is not found in

(a) brain

(c) tendons12. Nerve cell does not contain

(a) axon

,.--~.. -VK Biology~ IX 74

(b) calcium and phosphorus

(d) phosphorus and potassium

(b) blood

(d) cartilage

(b) spinal cord(d) nerves

(b) nerve endings

Tissues

(b) move upwards

(d) move sideways

(b) thick walled and specialized

(d) none of these

(e) tendons (d) dendrites

13. The muscular tissue which function throughout the life continuously without fatigue is

(a) skeletal muscle (b) cardiac muscle

(e) smooth muscle (d) voluntary muscle

14. Which of the following cells is found in the cartilaginous tissue of the body?

(a) Mast cells (b) Basophils

(e) Osteocytes (d) Chondrocytes

15. The dead element present in the phloem is

(a) companion cells (b) phloem fibres

(e) phloem parenchyma (d) sieve tubes

16. Which of the following does not lose their nucleus at maturity?

(a) Companion cells (b) Red blood cells

(e) Vessel (d) Sieve tube cells

17. In desert plants, rate of water loss gets reduced due to the presence of

(a) cuticle (b) stomata

(e) lignin (d) suberin

18. A long tree has several branches. The tissue that helps in the side ways conductions ofwater in the branches is

(a) collenchyma (b) xylem parenchyma

(e) parenchyma (d) xylem vessels

19. If the tip of sugarcane plant is removed from the field, even then it keeps on growing inlength. It is due to the presence of

(a) cambium (b) apical meristem

(e) lateral meristem (d) intercalary meristem

20. A nail is inserted in the trunk of a tree at a height of 1 metre from the ground level. After 3years, the nail will

(a) move downwards

(e) remain at the same position

21. Parenchyma cells are

(a) relatively unspecified and thin walled

(c) lignified

22. Flexibility in plants is due to

(a) collenchyma (b) sclerenchyma

(e) parenchyma (d) chlorenchyma

23. Cork cells are made impervious to water and gases by the presence of

(a) cellulose (b) lipids

(e) suberin (d) lignin

24. Survival of plants in terrestrial environment has been made possible by the presence of

(a) intercalary meristem (b) conducting tissue

(e) apical meristem (d) parenchymatous tissue

25. Choose the wrong statement

(a) The nature of matrix differs according to the function of the tissue.

(b) Fats are stored below the skin and in between the internal organs

(c) Epithelial tissues have intercellular spaces between them

(d) Cells of striated muscles are multinucleate and unbranched

Tissues 75

• Apical, lateral and intercalary meristem

• Permanent tissues: Simple and complex tissues

• Parenchyma, collenchyma and sclerenchyma

• Phloem and xylem

FA 8. Oral Assessment

Answer the following questions carefully.

1. What are the various types of tissues in plants?

2. State the functions of parenchyma.3. What are the functions of xylem and phloem)

4. Where is meristematic tissue found in plants?

5. What is the difference between striated and non-striated muscles?

6. Where is columnar epithelium found?

7. Give the functions of sclerenchyma.8. What is the function of neuron?

9. Write the names of cells found in the matrix of connective tissue.

10. What are tracheids and vessels?II. What is connective tissue?

12. Name the tissue associated with the conduction ohvater in plants.

13. Name the elements found in phloem.

14. What is the specific function of the cardiac muscle?15. Write two characteristics of a nerve cell.

FA 9. Paper Pen Test1. Answer the following questions

(a) Why are xylem and phloem called complex tissues? How are they different from one another?

(b) Describe the structure and function of different types of epithelial tissues.(c) Why is epidermis important for the plants?

(d) Give reasons for the following

(i) Meristematic cells have a prominent nucleus and dense cytoplasm but they lack vacuole.

(ii) Intercellular spaces are absent in sclerenchymatous tissue.(iii) We get a crunchy and granular feeling when we chew pear fruit.

(iv) Branches of a tree move and bend freely in high wind velocity.(v) It is different to pull out the husk of coconut.

(e) Differentiate between scelerenchyma and parenchyma tissues.

2. Fill in the blanks(a) Cork cells possess on their walls that makes them impervious to gases and

water.

(b) have tabular cells with perforated walls and living in nature.(c) Bene possesses a hard matrix composed of and _

(d) and are forms of complex tissues.

(e) have guard cells.(j) Husk of coconut is made of tissue.

(g) Xylem transports and from soil.

:----i- 78 Tissues L..-J

(b) adipose tissue(d) cartilage

(b) Columnar epithelium

(d) Cuboidal epithelium

(b) not limited to certain regions

(d) growing in volume

3. Multiple Choice Questions(i) Find out incorrect sentence

(a) Parenchymatous tissues have intercellular spaces.

(b) Collenchymatous tissues are irregularly thickened at corners.

(e) Apical and intercalary meristems are permanent tissues.(d) Meristematic tissues, in its early stage, lack vacuoles.

(ii) Which cell does not have perforated cell wall?

(a) Trachieds (b) Companion cell(e) siseve cells (d) Vessels

(iii) Intestine absorbs the digested food materials. What type of epithelial cells areresponsible for that?

(a) Stratified squamous epithelium

(e) Spindle fibres(iv) Meristematic tissues in plants are

(a) Localised and Permanent

(e) Localised and dividing cells

(v) Fats are stored in human body as

(a) cuboidal epithelium(e) bones

(vi) Voluntary muscles are found in

(a) Alimentary canal (b) Limbs

(e) Iris of the eye (d) Bronchi of lungs

(vii) Which of the following helps in repair of tissue and fills up the space inside the organ?

(a) Tendon (b) Adipose tissue

(e) Arelor (d) Cartilage4. Match the Following.

Column I Column II

(a) Filling of space inside the organs (i) Skin

(b) Striated muscle (ii) Cartilage

(c) Adipose tissue (iii) Alveolar tissue

(d) Surface ofjoints (iv) Subentaneous layer

(e) Stratified squamous epithelium (v) Skeletal muscle

if) Permanent tissue (vi) Cocalised thickening

if) Cellenchyma (vii) Sclerechyma

5. True or False.(a) Epithelial tissue is protective tissue in animal body.(b) The lining ofblood vessels, long alveoli and kidney tubules are all made up ofepithelial tissue.

(e) Epithelial cells have a lot of intercellular spaces.

(d) Cells of cork are dead, suberised and compactly arranged.(e) Voluntary muscles control the movement of iris of eye.

Tissues 79

SUMMATlVE ASSESSMENTTextbook Questions

1. What is a tissue?

Ans. Tissue is a group of similar cells which perform the same function and have a commonOrigin.

2. What is the utility of tissues in multicellular organisms?

Ans. Tissues are made up of group of cells carrying a specialised function. Each specialisedfunction is taken up by a different tissue. Since these cells ofa tissue carry out only a particularfunction, they do it very efficiently. For example, in human beings, muscle cells contract orrelax to cause movement, nerve cells carry messages, and blood flows to transport gases,food, hormones and wastes materials and so on. Likewise, in plants, vascular tissues (xylem,phloem) conduct water and food from one part of the plant to other parts. So, multicellularorganisms show division of labour through tissues.

3. Name the types of simple tissues.

Ans. There are 3 types of simple tissues:(i) Parenchyma

(ii) Collenchyma

(iii) Sclerenchyma

4. Where is apical meristem found?

Ans. Apical meristem is found in shoot apex and root apex of plants.

5. Which tissue makes up the husk of coconut?

Ans. Sclerenchyma tissue.

6. What are the constituents of phloem?

Ans. Phloem is made up offour types of elements:(i) Sieve tubes

(ii) Companion cells

(iii) Phloem fibres

(iv) PWoem parenchyma

7. Name the tissue responsible for movement in our body.

Ans. Muscular tissue.

8. What does a neuron look like?

Ans. A neuron consists of a cell body with a nucleus and cytoplasm, from which long thin hair-likeparts arise called dendrites. Each neuron has a single long part called the axon.

9. Give three features of the cardiac muscle.Ans. (i) Cardiac muscles are involuntary.

(ii) Cardiac muscle cells are cylindrical, branched and uninucleate.

(iii) Cardiac muscles show rhythmic contraction and relaxation.

10. What are the functions of areolar tissue?

Ans. Areolar tissue is a connective tissue. It fills the space inside tile organs, supports internalorgans and helps in repair of tissues.

11. Define the term 'tissue'.

Ans. A group ofcells that are similar in structure and work together to achieve a particular functionis called tissue.

80 Tissues

12. How many types of elements together make up the xylem tissue? Name them.

Ans. Four types of elements make up the xylem tissue. They are:(i) Tracheids

(ii) Vessels

(iii) Xylem parenchyma. and

(iv) Xylem fibres

13. How are simple tissues different from complex tissues in plants?

Ans. A simple tissue is made up of only one type of cell whereas a complex tissue is made up ofdifferent types of cells.

14. Differentiate between parenchyma, collenchyma and sclerenchyma on the basis of theircell wall.

Ans. The differences between cell walls of parenchyma, collenchyma and sclerenchyma are:

Parenchyma Collenchyma Sclerenchyma

Cell wall is primary. Cell wall is primary. Cell wall is secondary.

Cell wall is thin and made up of Cell wall has irregular thickening Cell wall is uniformly thick duevery less cellulose. of cellulose. to deposition of lignin.

15. What are the functions of the stomata?

Ans. The important functions of the stomata are:(il Exchange of gases with atmosphere.

(ii) Transpiration, i.e., loss of water in the form of water vapour.

16. Diagrammatically, show the difference in three types of muscle fibres.

Ans.

~ITTlTl111IillJI- =====-

....-

Intercalated disk Striations Nucleus Spindle-shapedNUCleus~;?SCle c~lIs

~~~rm~Trf1iili~~~:5~~ - s::

Cardiac muscle fibre Smooth muscle fibre Striated muscle fibre

17. What is the specific function of the cardiac muscle?

Ans. Cardiac muscles occur in the heart and bring about the rhythmic contraction and relaxationof the heart throughout life.

18. Differentiate between striated, unstriated and cardiac muscles on the basis of their structureand site/location in the body.

Ans. Differences between striated, unstriated and cardiac muscles are as follows:

Striated Muscle Unstriated Muscle Cardiac Muscle

Structure The cells of striated The cells of unstriated The cells of cardiacmuscles are long, muscles are long with muscles are cylindrical,cylindrical, unbranched pointed ends and branched and uninucleate.and multinucleated. uninucleate.

Location These muscles are attached These muscles are present Cardiac muscles areto the bones. in the alimentary canal, present in the heart.

blood vessel iris of theeye, ureter and bronchi.

Tissues 81

19. Draw a labelled diagram of a neuron.

Ans.Nucleus

Nodeof-__ranvier

~rocE2co:<

• ---SchwanncellsAxon

""I .Myelin sheath

20. Name the following:

(a) Tissue that forms inner lining of our mouth.(b) Tissue that connects muscle to bone in humans.

(c) Tissue that transports food in plants.

(tf) Tissue that stores fat in our body.(e) Connective tissue with a fluid matrix.

if) Tissue present in the brain.Ans. (a) Simple squamous epithelium

(b) Tendon

(c) Phloem(d) Adipose tissue

(e) Blood

. if) Nervous tissue

21. Identify the type of tissue in the following: skin, bark of tree, bone, lining of kidney tubule,vascular bundle.

Ans. Skin: Epithelial tissue (Squamous epithelium)Bark of tree: Cork (protective tissue)

Bone: Skeletal tissue (connective tissue)

Lining of kidney tubules: Cuboidal epithelial tissue

Vascular bundle: Complex permanent tissue-xylem and phloem

22. Name the regions in which parenchyma tissue is present.

Ans. Parenchyma is a simple permanent tissue present in the cortex and pith of stem and roots. Itis also present in the mesophyll ofleaves.

23. What is the role of epidermis in plants?

Ans. Epidermis is a protective tissue of plants. It provides protection to underlying tissues.Epidermis forms the outer covering of the entire plant surface. Epidermal cells on the aerialparts of the plant often secrete a waxy, water-resistant layer on their outer surface, whichprovides protection against loss of water, mechanical injury and invasion of parasitic fungi.In the roots, they help in the absorption of water.

24. How does the cork act as a protective tissue?

Ans. The cork cells are dead and do not have any intercellular spaces. The cell walls of the corkcells are coated with suberin (a waxy substance). Suberin makes these cells impermeable towater and gases. Thus, it protects underlying tissues from desiccation (loss of water fromplant body), infection and mechanical injury.

l:·----..u 82


1. Animals of colder region and fishes of cold water have thicker layer of subcutaneous fat.Describe why?

Ans. Fat-storing adipose tissue is found below the skin of animals of colder region and fishes ofcold water. Storage of fats acts as an'insulator and prevents the body of animals in colderenvironment.

2. If a potted plant is covered with a glass jar, water vapours appear on the wall of glass jar?Explain why?

:\ns. The potted plant release water in the form of water vapours from aerial parts of the plant.However, when a potted plant is placed inside a glass jar, water vapours remained inside andthus appears on the wall of the glass jar.

3. Water hyacinth floats on water surface. Explain.

Ans. Water hyacinth is an aquatic plant in which large air cavities are present in parenchyma togive buoyancy to the plants to help them float. Such a parenchyma type is called aerenchyma.

4. Which structure protects the plant body against the invasion of parasites?

:\ns. Epidermis, the enter protective layer of the plant body do not allow parasites to enter thebody due to(i) secretion of waxy, water-resistant layer on their outer surface, this aids in protection

against loss of water, mechanical injury and invasion of parasitic fungi.(ii) absence of intercellular spaces.

(iii) thicker enter walls.

EXERCISES

A. Very Short Answer Questions

1. What is a tissue?

2. What are the different types of plant tissues?

3. Define simple tissues.

4. What are tracheids and vessels?

5. What is the function of sieve tubes and companion cells?6. Give the names of elements found in phloem.

7. Which tissue of leaves has chloroplasts?

8. Write the names of living tissues of plants.

9. Write the names of animal tissues.

10. Give the functions of epithelial tissues.11. What is the function of ciliated epithelium?

12. Where is squamous epithelium found?13. What is connective tissue?

14. What are the two main types of fibres of connective tissue;>

15. Write the names of cells found in the matrix of connective tissue.

16. How many types of muscles are found in animals?17. What is the function of neuron?

18. Which of the muscle cells is uninucleated-smooth muscle or cardiac muscle?

19. Which cells are thick at the corners-parenchyma or collenchyma?20. Name the tissue associated with the conduction of water in plants.

(1 mark)

Tissues 83

21. What is the position of meristematic tissue in plants?

22. What is the main difference between meristematic and permanent tissues?

B. Short Answer Questions (2,3 marks)

1. Give two points of differences between striated and non-striated muscular tissues.2. Differentiate between the following structures:

(i) Trachied and vessel.

(ii) Sieve tube and companion cell.

(iii) Tendon and ligament.(iv) Collenchyma and sclerenchyma.(v) Areolar connective tissue and dense connective tissue.

(vi) Parenchyma and collenchyma.

3. Write short notes on any four of the following:

Collenchyma, sclerenchyma, glandular epithelium, connective tissue, cardiac muscle.4. Write notes on: Sieve tubes and Trachieds.

5. Write two characteristics of nerve cell.

6. How many types of elements are present in the phloem? Write their functions.

7. How many types of elements are found in the xylem' Give their functions.

8. What is the specific function of cardiac muscle?

C. Long Answer Questions (5 marks)

1. What is the function of erythrocytes (RBCs) and leucocytes (WBCs) in the human blood?2. What is tissue' Give a brief account of the chief types of tissues in plants.

3. Describe structure and various functions of connective tissues.

4. Give a brief account of chief types of the tissues in animals.

D. Practical-based Multiple Choice Questions

Tissues84

1. Neha offered a plate of mixed salad consisting of boiled potatoes grated cucumber slices ofraw tomatoes, very small pieces of an apple and slice of guava to her 70 years old grandmother who refused to eat the salad because one of the ingredients of the salad containedlots of sclereids and made it hard for her to chew. Identify it.(a) Guava (b) Tomato

(e) Cucumber (d) Apple

2. Cross section of a plant part shows the following cells. Identifythem.(a) Sclerenchyma (b) Parenchyma(e) Collenchyma (d) T.S. of phloem tissue

3. Prerna of Class IX got a scolding from an external examiner, when she wrote thefollowing statements as identifying features of cardiac muscles after observing theslide even under high magnification power in a compound microscope. Which of thestatement was wrong?(a) Always present in heart

(b) Presence of intercalated discs

(e) Faint striations

(d) Fewer mitochondria as compared to smooth muscles

l·----.-u

/L<~<---A

I+---B

4. The animal known as 'Ship of the desert' has hump made up of specific tissue whichprovides water at the time of scarcity. Identify the tissue.(a) Skeletal (b) Muscular

(e) Nervous (d) Adipose

5. A naughty student of class IX was pricking the live animals present in an aquarium inKerala. His prick led to the movement of animals away from him. Only one of the animalsdid not feel the pain due to the absence of nerve cells. It was(a) hydra (b) starfish

(e) crab (d) ponges

6. Identify the incorrect pair from the following set.(a) Nervous tissue - Excitability and conductivity

(b) Muscular tissue - Contractility

(e) Cardiac muscles - Self excitatory

(d) Smooth muscles - Self excitatory

7. Deepika Padukone, the famous Indian model was selected by Hemant Trivedi for a fashionshow to display his summer collection. The show was held in Toronto, Canada in an openground. As soon as Deepika reached the ramp, her body started shivering. This happenedin order to(a) check the dispersion of body heat due to low temperature

(b) increased flow of blood towards skin

(e) increased heat production by muscles function

(d) increased heat production by muscles contraction

8. Rohit was aspiring to become Mr. India, so he joined a gym to build his body muscles. Onday one, he exercised for about an hour continuously. Next day, he was in a bad state andfound it difficult to move his legs and arms due to cramps. The cause was(a) cardiac muscles got tired due to constantly pumping 02 to the muskes

(b) pyruvic acid was accumulated in all three types of muscles which led to pain

(e) lactic acid was accumulated in striated muscles

(d) ethanol was accumulated in striated muscles due to anaerobic respiration by the cells

9. During an entrance exam for Agriculture Research Services, the name of the tissue thatgives rises to jute fibres was asked. Only one out of four candidates gave the correct answer.Identify the person.(a) Amit wrote that xylem fibres give rise to jute fibres

(b) Ajita write that phloem fibres

(e) Alpana sclereids

(d) Rachit sieve tubes

10. You are shown two slides of plant tissues: parenchyma andsclerenchyma. You can identify the sclerenchyma by the(a) location of nucleus (b) thickness of cell wall

(e) size of cells (d) position of vacuoles.

11. Label 'N and 'B' correctly in the following diagram.(a) A - Nucleus, B - Dendrite

(b) A - Dendrite, B - Axon

(e) A - Axon, B - Dendrite

(d) A - Dendrite, B - Nucleus

Tissues 85

12. Four slides were observed under the microscope for spot test as shown below. The correctidentification of the four spots is

[A] [B] [C] [D]

(a) A: onion peel B: cheek cells C: sclerenchyma D: parenchyma

(b) A: cheek cells B: parenchyma C: sclerenchyma D: onion peel

(c) A: parenchyma B: cheek cells C: onion peel D: sclerenchyma

(d) A: sclerenchyma B: onion peel C: parenchyma D: cheek cells

13. Raj observed nerve cells under the microscope, and made the following sketch. The mistakein his drawing is the cyton with(a) cilia (b) dendrites

(c) nudeus (d) cytoplasm.

14. Observe the location and shape of the nuclei in the four drawings of the striated musclefibres given below. The drawing that most resembles the slide of striated muscle fibreunder the microscope is

[A] [B] [C] [D]

(a) A (b) B

(c) C (d) D

Answers

1. (a) 2. (c) 3. (d) 4. (b)

5. (d) 6. (d) 7. (d) 8. (c)

9. (b) 10. (b) 11. (b) 12. (d)

13.(a) 14. (c)

III

,,~._---86 Tissues

Chapter: Three

~M~[f@\Yl®M®mJ1t DmJ[P@@cQJ [ffi®~@lliJ [f~®~

FOOD RESOURCES: PLANTSCan you stay a single day without food? You may, but at the end of the day you

will feel weak, giddy and might as well fall ill.

Food is essential for all living beings. Food contains carbohydrates, fats, proteins,vitamins and minerals. We require these for our body growth and development,maintaining a good health and getting energy for work.

Plants make their own food from air, water, sunlight and a green pigmentpresent in them-chJorophyll, through a process called photosynthesis. That is whythey are called autotrophs. However, animals including man cannot make theirown food. They depend on plants and other animals for food. So they are calledheterotrophs.

The main source of man's food has been plants-cereals, pulses, vegetables,fruits, etc. are provided to man by plants. Products like milk, honey, eggs and meatare yielded from animals. Since time immemorial, man has been growing crops inthe fields and rearing animals to obtaiu food and satisfy his hunger. Man has beencontinuously trying to produce more and more food of better and still better quality.

ow with the growth of population it has become all the more important to increaseits quantity and improve its quality. Our country is the most densely populatedcountry of the world with a population of 1.04 billion people. According to estimates,India's population will stand at 1.34 billion by the year 2020. To support such ahuge population we will require at least 240 million tonnes of grain productionevery year. Our scientists like Kurien and Swaminathan have put a lot of efforts toincrease the food production of our country and make it self-sufficient and have alsoachieved some success in this regard.

We have had the green revolution in late 1960s which contributed to increasedfood grain production, followed by the white revolution, which led to increased milkproduction, the blue revolution, the yellow revolution and the golden revolution.(see Table 3.1).

"10 matter how much success we have had in this regard, but in this processwe have exploited the environment so much that it has led to its degradation. owit has become important that we take care of the environment too, while we exploitits resources to satisfy our needs. Efforts are afoot in this regard also. Chemicalfertilisers like urea have been replaced by organic manures. Use of pesticides likeDDT, etc. which are known to affect the health ofmen and animals drastically, have beenminimised and replaced by biological means. Organic farming is practised nowadays.

Also, by increasing the production oHood, we cannot do away with the problemof hunger and malnutrition in our country, for, people should have money to have

Improvement in Food Resources

M.S. Swaminathan

• The founder of thegreen 1'evolution wasM.S. Swa11linallzan.

87 :'i::;,=,=::;1;m)1-__":j

Table 3.1: Programmes for increasing food production in our country

Programmes

Green Revolution

White Revolution

Golden Revolution

Yellow Revolution

Blue Revolution

Food Resources

Foodgrains

Milk

Pulses

Oil

Fish

an access to it. Hence people should be given employment and made self-sullicito earn their own living. Otherwise, grains would be simply stored in warehousethe businessmen.

~mg;:.j

• Crops m'eagricultural plnntsg;rown in communityin large areas.

Crop ProductionAgriculture is a profession of a large number of human population. Our

economy is based on agriculture. Most of our people live in villages and are busy inagriculture. In the recent decades, agricultural production has increased manifolddue to the development of new high yielding varieties of seeds and crop plants(Green revolution). Food grain production has been four times from 1960 to2004 with just 25% increase in cultivable level area. Prof. M.S. Swaminathan wasthe architect of green revolution in India which occurred in late 1960s. He hadbeen Director ofIA.R.i., and Director General ofI.C.AR. New Delhi and DirectorGeneral of International Rice Research Institute, Manila. He also established M.S.Swaminathan Research Foundation in Chennai. He recognised the value ofMexicandwarf wheat variety and introduced that in India. Its yield was better than the earlyvarieties. But it needed more irrigation and fertilisers. In green revolution, use ofpesticides and weedicides were also increased. Swaminathan was called the fathe' ofeconomic ecology by L.'\. Em'ironment programme. He got world Food Prize forthe contribution he made against hunger in India.

Table 3.2 Food Production in India in 1999

• Cultivation isgrowing ofcropsfrom seeds.

Food products Million tonnes Animal products Million tonnes

1. Cereals (wheat, rice) 203.0 L ~1eat 4.7

2. Pulses 16.1 2. Poultry meat 0.55

3. Vegetables 59.4 3. Fish 3.2

4. Roots and tubers 29.7 4. Milk 77.2

5. Fruits 38.6 5. Aquaculture 2.0

6. Edible oil 9.1

Total 355.9 I I 87 .65

The production ofcereals is more in comparison to meat production. In India,vegetarian population is greater than that of non-vegetarians. Non-vegetarians alsoneed cereals since they are not 100 per cent non-vegetarians. Cereal crops suchas wheat, rice, maize, sorghum, etc., are seasonal crops. These are harvested in aseason ofabout five months. Cereals were domesticated earlier than any other groupof useful plants of today. Beside cereals, pulses and oil seeds were also discovered.

The wheat, rice, maize, sorghum, pulses (umd, arizaI', moong, etc.), oil seeds(mustard, soyabean, sunflower), vegetables and fruits are obtained from plantsources.

.~,~88 Improvement in Food Resources

Food giving plants are thus, as follows:

(i) Cereals, e.g., wheat, rice, maize, jowar, bajra, etc. Wheat is mostly consumedin Punjab, Haryana, Uttar Pradesh and Madhya Pradesh. Rice eating peoplebelong to the states of Bihar, West Bengal, Assam, Orissa and the southernstates of India. Jowar and bajra are mostly used in Rajasthan and Gujarat.

(ii) Pulses, e.g., arhar, gram, peanuts, 1IIoong.(iii) Oil seeds, e.g., mustard, cotton seeds, groundnuts, sunflower, soyabean, coconuts.(iv) Vegetables, e.g., potato, onion, brinjal, cabbage, carrot, cauliflower, lady's

finger, gourd, etc.

(v) Fruits, e.g., banana, mango, orange, apple, pineapple, lemon, peach, etc.

Table 3.3 Some Food Items

Carbohydrates Fats Proteins Minerals\. Wheat \. Groundnuts \. Milk \. Green leafy

vegetables2. Rice 2. Vegetable oil from 2. Eggs 2. Beans

sunflower, soyabean,mustard, ground nuts.

3. Jowar 3. Animal fat from meat 3. Meat 3. Ragiand fish

4. Bajra 4. Fish 4. Dry fruit(almonds, etc.)sea weeds

5. Potato 5. Bean 5. Liver

6. Tubers and rhizomes 6. Pulses 6. Eggs7. Beet root 7. Grounclnuts 7. Sea foods

8. Vegetables 8. Peas

Cereals (wheat, rice, maize, millets and sorghum) provide us carbohydrates,which is the main source of body energy. Calorific value of carbohydrate is 4.1 kcal.We get protein from pulses like gram, pea, black gram (urad), green gram (1Iloong) ,pigeon pea (m'har) and lentil (nzassur). Calorific value of protein is 5.65 kcal. Proteinsare used up in the body for making muscles etc. Thus, proteins are 'buildingmaterials' of the body. Oil seeds like soyabean, groundnut, sesame, castor, mustard,linseed and sunflower provide us with necessary fats. One gram of fat producesabout 9.45 kcal of energy. Thus, fats provide more energy than carbohydrates andproteins. Spices, vegetables and fruits provide vitamins and minerals besides smallamount of carbohydrate, protein and fat. Fodder crops are used as food for thecattles.

Crop Seasons

The various types of crops (cereals, pulses, etc.) need different climaticconditions, temperature and photoperiods (duration of sunlight) for their growthand fruiting. On the basis of season, crops are of two types: kharif and rabi crops.

Kharif Crops like rice, maize, jowar and bajra belong to cereals, and pulseslike urad, arhar, and 1Iloong are grown in June after the first rains of the rainy season.Rainy season is from June to October.

Rabi Crops are wheat (cereal) and pulses like gram and pea and oil producingplants like mustard and linseed are grown in November. Rabi season is fromNovember to April.

Improvement in Food Resources 89 VK Biology IX ----,.

...._-- VK Biology IX 90

There are certain crops which are grown between March and June and a:known as Zaid crops.

Improvement in YieldsAgricultural practices can happen in three stages:

1. Crop variety improvement: This stage includes selecting ofseeds, hybridisatiand genetic engineering to get an improved variety of crops.

2. Crop production management: The second stage is nurturing of the croplants through nutrients management, irrigation, cropping patterns, etc.

3. Crop protection management: The third and the final stage includprotection of the growing and harvested crops from damage. This is dontethrough proper storage, pest control and disease control.

activity 1• Visit the llem-by agriculture fann in both seasons (kharif and mbi season) and find OW

which CTOPS are sown. Ask the farmer which manure or fertiliser is being applied.

Crop Variety ImprovementCrop variety improvement is done for:

1. improving the productivity of crops.

2. improving the quality of yields.

3. developing crop varieties that are resistant to drought, water logging, heatand cold.

4. develop crop varieties that are resistant to diseases.

This involves improvement in genetic makeup of a plant in relation to itseconomic use. This involves

(i) selection of an improved variety of seed for planting.

(ii) hybridisation of genetically dissimilar plants to produce a new kind, betterin quality.

I Plant Breeding

Crop improvement mostly involves plant breeding. The knowledge of geneticsis essential for plant breeding. The aim of plant breeding is to produce a superiorquality of plant and it should be adaptable to that environment, where it will begrown. The common methods of plant breeding are:

1. Selection 3. Induced mutations

2. Hybridisation. 4. Genetic engineering.

1. Selection

It is the process of choosing the plants with desirable characters. The plantswith useful and desirable characters are chosen and maintained. The plants whichare not useful and have undesirable characters are neglected and eliminated. Thepresent day crop plants are being thus evolved due to continued selection of naturalvarieties of useful plants, over a long period of time_ The selection is continuedwith each generation during which some characters are lost naturally while othersbecome stable. Such plants look totally different from their wild ancestors. This isthe process by which wheat and maize plants were selected. In the past, man had


selected a wild wheat having an inflorescence axis with intact floral stalks. Similarlymaize variety having seeds embedded tightly were selected. These were continuouslybred, and undesirable plants amongst them were discarded. Thus, the present daywheat and maize were produced.

There are two methods of selection:

(i) Mass selection, and (ii) Pure line selection.

(i) Mass selection: It is the oldest and commonest method of breeding cropplants. In this method, large number of plants having similar characters areselected and their seeds are mixed and grown together. Out of these plantswhich have desirable characters like height, disease resistance, growth rate,grain characters, etc., are selected and their seeds are again grown. From theseplants, again undesirable plants are eliminated. This procedure is repeated tillthe desired plants and their seeds are obtained. This is the oldest and mostcommon method of breeding crop plants. It is also known as the "Germanmethod of crop breeding".

By self-pollination or self-fertilisation process, plants are multiplied and seedsare obtained. But it has a limited use for self pollinated plants. It is importantfor cross pollinated plants.

(ii) Pure line selection: Pure line is a progeny of a single self-pollinated (selffertilised) individuals having same type of genetic characters. In this methodalso desirable plants are collected from a large different genetic type ofpopulation. These selected plants are self-pollinated for a few generations tilla true breed or pure line progeny is obtained. Nter obtaining a true breed,these plants are multiplied on a commercial scale. Pure lines are speciallyimportant in the improvement of self pollinated crops. Most of the improvedvarieties of wheat, rice, pulses, oil seeds, etc., have been developed by thisprocess. Concept of pure line and pure line selection was given by Wilhelm L.Johannsen (a Danish geneticist).

2_ Hybridisation

It is a process in which two genetically dissimilar plants (two different varietiesor between two different species ofsame genus or inter generic, i.e., between differentgenera) having desired characters are crossed or mated and brought together intoone individual. This individual having known desired characters is called hybrid. Itinvolves following steps:

(i) Selection of parents: Plants selected for hybridisation should have desiredcharacters. One should be well adapted to that area and the other should havedesired characters which are not found in the first chosen type.

(ii) Emasculation: It is the removal of anthers or stamens or killing of pollengrains of a flower without damaging the female reproductive organs. Thus,self pollination and self-fertilisation is avoided. In bisexual plants, the maleflowers or inflorescences are removed to prevent self pollination. In unisexualspecies, male plants are removed.

(iii) Bagging: Nter emasculation, the flowers on inflorescence are enclosed inpolythene bags or butter paper bags to prevent random cross pollination.

(iv) Cross pollination: In crossing, mature, fertile and viable pollens from adesired male plant are collected and then placed or dusted on the stigmaof the other female plant. Nter dusting, the female plant is bagged. Thus,natural fertilisation occurs which results in the formation of seeds. Matureseeds of F1 generation are harvested, dried and stored. Later these seeds aregrown, which give F I hybrids.

Improvement in Food Resources 91 VK Biology IX

-VK Biology IX"'..---- 92

Hybrid Vigour or Heterosis

This F1 hybrid is superior to the two genetically dissimilar parents. Terheterosis was proposed by George H. Shull. Heterosis is measured in terms of sizgrowth rate, yield, etc. These cross pollinated species are heterozygous, i.e., differefrom both the parents. Heterosis produces useful characters, like increased sizvigour, resistance to diseases and pests, and yield, etc. It is important in crops likmaize, wheat, sorghum, bajra, rice, cotton, sugar-beets, sunflower, tomato, brinjonion, etc. Hybrid vigour is lost by continuous inbreeding and hence parental lineare to be maintained, for producing seeds. Hybrid vigour is the best maintained invegetatively reproducing crops, like mango, guava, apple, chrysanthemum, dahlia.etc.

activity 2• Students should visit nearby agricultuml fields and observe diffeTences of the same crop

grown in different fields. Students may ask the fanners why there is diffeTence ofsame crop.Note down the factors for the difference.

Advantages of H ybridisation

(i) More vigorous and well adapted varieties can be produced.

(ii) Hybrid possesses new genotypes.(iii) Variety produced has superior characters.

(iv) Hybrids mature early and need better fertilisers.

(v) Hybrid crop yield will also be more.

3. Induced Mutations

Sudden heritable changes are called mutations. Mutations could be natural(spontaneous) or artificial (induced). Induced mutations can be done by chemicaland physical agents. These are of great importance in crop imp!·ovement. Forinduced mutations irradiations is commonly used. C060 or Cs' , are used forproducing gamma rays. This facility exists in Nuclear Research Laboratory, IARI,New Delhi.

Sharbati sonara wheat variety was produced by irradiation of Sonara 64 withgamma rays. Similarly Pusa lerma was produced from Lerma rojo 64. Wheat NP836 is also produced by the same method. Improved varieties of rice, pea, cotton,etc., are also produced by induced mutations.

4. Genetic Engineering

For crop improvement, manipulation of gene (Dl A) instead of completechromosome set is done. In it a specific segment of DNA from living organisms isisolated and purified. DJ A sequence is broken off at two desired places to separatespecific part of DNA. This part is later inserted into the DNA of the bacterial plasmidat a desired place. This DNA, thus obtained is called recombinant DNA. The methodused is called genetic engineering. By this method one can add, or remove or repairpart of genetic material and thus can change the qualities of an organism.

Objectives of Varietal Improvement

(1) Improvement of yield: The aim is to develop high yielding varieties (HYV) ofcrops that will be economically beneficial.

(2) Development of disease resistant crop. Crop should be db resistant, i.e.,drought, water-logging, salinity, heat, cold, frost, etc., and also biotic resistant,i.e., disease resistant. Such a crop gives a good yield.

Improvemex' r

(3) Better quality of crop: As regards economic value, protein quality of pulses,oil quality in oil seeds and preservity of vegetables and fruits, are taken intoconsideration to estimate better quality of crops.

(4) Photo-insensitivity and thermo-insensitivity of the crops: This helps incrossing the cultivation boundaries, e.g., high yielding wheat variety andMACS 2469 are able to tolerate high temperature, and are insensitive to light.

(5) Early and uniform maturity: In some of the long duration crops, their ear"maturing varieties will be beneficial for harvesting the double and multiplecropping systems. It also reduces the cost of crop production. C niformmaturit) makes the harvesting easy and reduces the loss of produce duringharvesting.

(6) Wider adaptability: Varieties which have wider adaptabilities should bedeveloped. These varieties may be developed under different environmentalconditions. Example is ICPH 8 hybrid pigeon pea which matures in a shorttime and is disease resistant against fusarium wilt and sterility mosaic. Itsyield is also 30% to 40% more than the popular breed. It may be produced indrought conditions as well as high-moisture conditions.

(7) Desirable agronomic traits: Desired agronomic traits give higher produce,such as high tillering, tall, profusely branching characters of fodder crops, anddwarf character of cereals. High yielding variety of wheat are Sonara 64, Hira,Moti, Kalyan sona and Sharbati sonara. HYV of Paddy are Pusa 205, IR 8,Padma and Jaya.High yielding varieties of cereals, fodder crops, oil seed crops, fruits, etc., canthus be developed by breeding and hybridization processes.

Crop Production Management

Input and yield have a correlation. Better the input, better is the yield and forimproving the input a systematic approach of management is required.

This involves

(i) supplying proper nutrients to the crops for its nurturing,

(ii) ensuring that crops get water at the right stage during their growingseason.

(iii) use of different ways of growing crops to give the maximum output.

I Nutrition Management

Plant Nutrition

Plants need many inorganic and organic substances (nutrients) for theirgrowth and reproduction. All these substances which plants take from outsideconstitute their food or nutrition. On the basis of their nutritional need, plantsare classified into autotrophs and heterotrophs. Autotrophs are self-nourishing,they manufacture their own organic food and require only inorganic substancesfrom outside. All green plants and photosynthetic bacteria are autotrophs. Theyobtain their nutrition mainly from soil in the form of inorganic ions. Heterotrophsneed both organic and inorganic substances from outside. Saprophytes Putrefyingbacteria like Bacillus and fungi [all fungi lack chlorophyll, (e.g., Mucor] and parasiticbacteria and fungi are heterotrophs. They do not manufacture their own food; theyobtain it from other organisms. Plant nutrients are the mineral elements neededby the plants for their growth, development and maintenance. The nutrients takenby the plants from the soil are many more in number (13) than those taken from


water and air (3). Nutrients taken from air and water are more important, sincethey constitute about 97 to 99.5% of total plant tissue. Though, plants absorb a largenumber of elements from the environment but only the following sixteen elementsare found to be essential nutrients for the plant nutrition:

1. Carbon 2. Oxygen 3. Hydrogen 4. Nitrogen

5. Phosphorus 6. Potassium 7. Calcium 8. Magnesium9. Sulphur 10. Iron 11. Manganese 12. Boron

13. Zinc 14. Copper 15. Molybdenum 16. Chlorine

Macronutrients

Plants require ten elements in relatively large amounts, carbon, hydrogen,oxygen, phosphorus, potassium, nitrogen, sulphur, calcium, magnesium and iron.These are called macronutrients. Out of these, last seven, P, K, N, S, Ca, Fe andMg are present in the soil and are called mineral elements. Oxygen, hydrogenand carbon are provided to the plant by oxygen gas, water and carbon dioxiderespectively.

Micronutrients

These are also essential for higher plants, but are required in very smallamounts. Hence, these are called micronutrients or trace elements. These arecopper, zinc, boron, molybdenum, chlorine, etc.

Table 3.4 Sources of Plant Nutrients

Air Water Soil

Nutrients Oxygen and Hydrogen Nitrogen, phosphorus, potassium, calcium,carbon sulphur, iron, magnesium, manganese, boron,

zinc, copper, molybdenum and chlorine.

• Mojo>' SOU1"CeS ofplant nutrientsare manures andfertilisers.

• Hydrogen, Oxygenand Carbm fOTln94% of the totalplant tissue.


Micronutrients

Found in plants in traces.

Concentration is less than 1 mg per g ofdry weight of plant.

Toxic if present in more than requiredquantity.

Examples: Zinc, Manganese, Copper,Chlorine, Boron, Molybdenum, etc.

Macronutrients

Found in plants in large quantities.

Concentration is more than 1 mg per gdry weight of plant.

Not toxic even if present In excessquantity.

Examples: Carbon, Hydrogen,Oxygen, Nitrogen, Calcium, Potassium,Phosphorus, Magnesium, Sulphur, Iron.

I.

2.

4.

3.

S.No.

I Use of Manures and FertilisersManures and fertilisers increase the fertility of the soil of crop fields. They also

remove the deficiency of plant nutrients of the soil. They are used to increase thecrop production.

Carbon, hydrogen and oxygen are indispensible for plant growth. Theyconstitute about 94 per cent of the total dry weight ofthe plant. Carbon is essen'for the synthesis of carbohydrates and fats. Oxygen and hydrogen are obtained frowater absorbed from the soil. Some oxygen is also absorbed from the atmosphere.

Nitrogen is absorbed from the soil in the form ofnitrate ions (nitrates ofcalcium,potassium, ammonium and sodium). Its deficiency in plants causes chlorosis. Leavesbecome pale or yellow. Formation of red and purple patches or streaks in stems, leafveins and petioles. Sulphur is absorbed by the plants as sulphate ions. Its deficiencyalso causes chlorosis in young leaves.

Table 3,5 Differences between Macronutrients and Micronutrients

94VK Biology IX

1. Manures

Manures are natural fertilisers which are being used since ancient days.~anures add small quantities of nutrients and large quantities of organic matterm the soil and make the soil soft for the better growth of root system and in turnplant growth. Capacity of holding water in the soil, etc., also increases. The microorganisms of the soil, beneficial to the soil and crop also get food. Manures arerequired in bulk quantities in comparison to chemical fertilisers. Large quantities oforganic matter in clayey soils help in drainage of water and also avoid water logging.

Types of Manures

Manures are of three types:

(I) Farm Yard Manure (2) Compost (3) Green Manure

(1) Farm yard manure (FYM): It is the decomposed matter of cattle dung(faecal matter), urine and litter, i.e., bedding material used in winter monthsat night under cattles. It also includes the leftover fodder in their manures.These materials are dumped daily in especially constructed pit away from thecattle shed. Action of microbes (e.g., bacteria, fungi, etc.) developed in thisexcreta, converts (decompose) it into manure, which is ready to spread inthe crop fields. Farmyard manure is used in field before the sowing of crop,i.e., in October and in May/June in northern India. FYM is rich in potassium,phosphorus and nitrogen. It contains about 0.5 per cent potassium oxide,0.15 per cent phosphorus pentoxide and 0.5 per cent nitrogen.

(2) Compost: It includes farm and town refuge (e.g., vegetable matter, animalrefuge such as excreta of domestic animals and stray animals, human faecalmatter (sewage, etc.) stored in open fields beyond the limits of town (humanpopulation). Like FYM, it is also a biological process in which aerobic andanaerobic microorganisms decompose the town and city garbage and sewagewaste into compost. Decomposition occurs between 3 to 6 months. Compostfrom town refuge contains about 1.4 per cent nitrogen, 1.0 percent phosphoruspentoxide and 1.4 per cent potassium oxide. While farm compost contains0.5% nitrogen, 0.15% P205 and 0.5% K20.

Method of preparing compost: For making compost, a trench or pit of 4 to5 m long, 1.5 to 1.8 m broad and I to 1.8 m deep is dug. In it a layer of mixedrefuse is spread. It should be about 30 cm in thickness. This is moistened withwater and cattle dung or water and earth. Over it again mixed refuse is addedwhich rises to a height of 45 to 60 cm above the ground level. ow the top iscovered with a thin layer of earth. This is kept as such for 3 months, then itis taken out of the trench and formed into a conical heap. Again moisten it ifnecessary and cover it with earth. Leave it again for one or two months. Nowthe compost is ready to use in the fields.Town sewage is also recycled mechanically in activated sludge system in whichsolid wastes settle down at the bottom of the plant. It is called sludge. Theupper clear water (sewage water) is being used in irrigation purposes and theorganic waste is dried and used as manure.

(3) Green manure: In green manure, generally leguminous as well as nonleguminous herbaceous plant seeds are sown in summers before the rainyseason for about 6 to 8 weeks. These are sunhemp (Crotalaria juneea) , berseem(Egyptian clover-Trifolium alexandrium) , sesbania or dhaincha (Sesbaniaaeuleata) and guar or cluster bean (Cyamopsis tetragonoloba), cowpea (lobia),lentils (massur) , etc. These plants near the onset of monsoon are ploughedand buried in the field at a tender stage, i.e., at flowering stage. In the rainy

• Manw-es are used inbulk before sowingseeds (croP).

• Composting is abiological processin which bothaeTobie andanaerobicrmcroorganzsmsdecompose organic"//Illtler in 3-6months.

rovement in Food Resources 95 VK Biology IX --'",

season these plants get decomposed with the help of decomposers. Then thenew cereal crop is sown. Green manure adds nitrogen and organic matter inthe soil. This adds to the fertility of the soil. It forms a protective soil coverand thus checks soil erosion and leaching. It increases the crop yield by30 to 50 per cent. Green manure is used in this region by some large farmers.l:.artll\mrms in the soil especially after rains turn down the soil. They feedon soil containing organic matter and their casting is also rich in organicmatter. They make the soil porous and increase the soil fertility. This type ofcomposting is called \<,rmie 'llpostin;.,.

• Ft1tilisers arec01nmerciallyprepared and richerin nutrients thanmanures.

• Fertilisers are usedin small quantities inlhe field.

I 2. Fertilisers

These are chemical fertilisers, manufactured commercially. They are richer innitrogen, sulphur, phosphorus and potassium. They are better than the manuresas regards nutrients and are thus used in small quantities. Fertiliser is a chemicalcompound, either inorganic or organic, containing one or more essential plantnutrients. Fertilisers, thus, increase the temporary fertility of soil and crop yield. Inevery crop, every time the crop is sown, these fertilisers are added to the soil. Thevarious types offertilisers are: nitrogenous, phosphatic and complex. It is suggestedto the farmers that before the application of these fertilisers, one should get thesoil tested, if the soil needs nitrogen or phosphorus or potassium or all the threeelements.

Types of Fertilisers

(i) Nitrogenous fertilisers: These are rich in nitrogen element. These areurea, sodium nitrate, ammonium sulphate, ammonium nitrate and calciumammonium nitrate. These are better for vegetative growth.

(ii) Phosphatic fertilisers: These are rich in phosphorus. These are phosphates andsuperphosphates. Phosphatic fertilisers are good for better fruit production.

(iii) Potassic fertilisers: These are rich in potassium, a micronutrient of plants.These are potassium chloride, potassium sulphate and potassium nitrate.

(iv) Complex fertilisers: These contain two or three elements-nitrogen,phosphorous and potassium. These are urea, ammonium phosphate, nitrophosphate, and diammonium phosphate.

Chemical fertilisers should be used judiciously and carefully. Heavy dose ofnitrogenous fertilisers destroy the crop. Testing of soil before the applicationof fertilisers is essential. On the basis of the deficient element in the soil,fertiliser should be used. Overuse offertiJisers decreases the fertility ofthe soil.Heavy doses of chemical fertilisers get washed off through irrigation throughdrainage and enter rivers, lakes, streams, etc. and pollute them. This disturbsthe natural ecosystem.

Table 3.6 Comparison of Manure and Fertiliser

....... VK Biology IX 96

S.No.

I.

2.

3.

Manure

It is a natural, organic decomposedanimal waste (dung) and vegetative,vaste.

It contains small amounts ofnitrogen,phosphorus and potassium.

It increases the humus in the soildue to great amount of the organicmatter.

Fertiliser

It IS a commercially preparedinorganic or organic compound.

It is rich in nitrogen, phosphorus andpotassium.

It does not add humus in the soil.

Improvement in food Resources

,'j Biofertilisers: These are biologically active products of bacteria, algae andfungi. They enrich the soil nutrients especially nitrogen. These includenitrogen-fixing microorganisms. Biofertilisers are used for specific crops suchas legumes (pulses), oil seeds and rice. They provide nitrogen to the cropplants. They are not used as an alternative to the chemical fertilisers, but playa supplementary role of providing nitrogen to the nitrogen deficient soil andcrop plants. Some of the biofertilisers used in India are legume RhizobiumsJlllbiosis, Azolla algae (Anabaena sYlllbiosis), free-living bacteria (Awlobacler andBacillus PO(\"III)"XI.l) living in the soil and fix atmospheric nitrogen. Cyanobacteriaor blue-green algae are also nitrogen fixers and Mycorrhiza is in symbioticassociation of fungi with roots of certain seed-bearing plants. Fungus absorbsnutrients from the soil and provides them to the host cells. Rhizobium hassymbiotic relationship with roots of leguminous plants. Root nodules areformed due to fixation of atmospheric nitrogen by bacteria. They also leavelarge amounts of nitrogen in the soil which is useful for the next crop.

Manure is cheap and is prepared by fertilisers are costly because they areevery farmer in villages. prepared in factories and also bear

IGovernment tax.

Manure is applied to the crop fields It is applied to the crop fields afterin bulk before the sowing season. germination or at the time of sowing

in a very minute amount.

• Themostimporlant sourcesof biofeTtilisers isthrough Ihe use oflegume-Rhizobiumbacteria.

Fertilisers are nutrient specific.i.e., contain nitrogen, phosphorus,potassium. These are absorbed by theplant roots, being soluble in \vater.

Manure is not nutrient specific. Itcontains all the nutrients in smallamounts absorbed by the plantsslowly from organic matter.

6.

5.

4.

FORMATIVE ASSESSMENTF" the 'l.ks

1. The crops which are grown in the rainy season are called crops.

2. The crops which are grown in the winter season are called _crops.

3. Hybridisation of crops refers to crossing between genetically _plants.

4. Wheat, gram, peas, mustard and linseed are crops.5. required by plants include nitrogen, phosphorus, potassium,

calcium, magnesium and sulphur.

6. The process in which farm waste materials like livestock excreta, vegetablewaste, sewage waste, straw eradicated weeds, etc. are decomposed in pits isknown as-----

7. Fertilisers are washed away due to excessive irrigation and are not fullyabsorbed by the plants which leads to _

8. is a farming system with minimal use or no use of chemicalsas fertilisers, herbicides, pesticides, etc. and with a maximum input of organicmanures, recycled farm wastes and bio-agents with healthy cropping system.

9. On the basis of the kind of biological material used, manure can be classifiedas _

10. Abiotic streeses in crop production include and

provement in Food Resources 97

.-:.--- 100

4. "Vater also serves as a medium where enzymatic reactions occur.5. Besides, the seed coat becomes soft after absorbing water and allows the

developing embryo to come out of seed.6. Too much water in the field inhibits aeration of the soil.

7. Irrigation after germination of seeds and some growth is essential for theproper growth of root systems and aerial branches (tillers). If the soil lacksmoisture, the crop plants become pale and finally dry up.

8. Water is essential for the solubility of nutrient elements. The soil nutrientsget dissolved in water and are absorbed by the plant's root systems. Chemicalmanures are also applied to the crop fields before irrigation. Mter applicationof fertilisers, crops are irrigated.

9. Except paddy crop, no crop needs standing water, which causes wilting ofplants.

10. Water logging in the field causes salinity ofthe soil. It reduces the fertility ofsoil.Water needs for different crops is different. Therefore, it should be usedjudiciously.

I Irrigational Requirements of Various Crops

Each crop needs a specific quantity of water at various stages of growth andfruiting. Some crops like paddy (rice) require more water. Plantation of paddyseedlings is done in water-filled fields. For their growth and development continuousirrigation is required. Paddy fields should be well watered. Therefore, this crop issown In raIny season.

Maize, jowar and bajra need very less water, though sown in rainy seasonstarting from June. Wheat, gram, pea also require less water. These are winterseason crops. Pulses also require less water.

Type of crop: Timing of irrigation for various crops is also essential for a goodyield. At the time of sowing, soil should contain enough moisture for germination.Irrigation ofa wheat seedling is required after it attains about 6 inches size. Wheatat the time of maturity needs no irrigation. If any how rainfall occurs at this time,the plants bend or fall in the field affecting the yield of crop.

Nature of soil and their need of water: Various types of soils have differentrequirements ofwater. Sand,' soil is porous. Its particle size is relatively larger. Watereasily percolates down and hence its water retention capability is very poor. Sandysoil, thus, needs frequent irrigation, so that plants may get enough water for theirgrowth and fruiting. Example is Rajasthan where soil is sandy. There crops likejOWal~ bajra and maize are sown, which need very less water. They mostly dependon rains because facilities of irrigation are not proper.

Clayey soil particles are relatively small and have very less permeability. Itis capable of retaining water for a long time. Hence, frequency of irrigation iscomparatively less and the crop plants get water for a long time. Thus, propermanagement of irrigation for various crops is essential for getting good crop yield.

I Irrigation System

The common method ofirrigation in India are wells, tube wells, pumps, canals,tanks, river-valley system and river-lift systems. Irrigation is essential at variouslevels of crop production, such is sowing, tilling, flowering and fruiting. Some wellknown inigation systems are given as follows:


1. Wells: Wells are bored at such placeswhere there is enough ground water isenough. These are of two types:(i) Dug wells, and

(ii) Tube wells.

(i) Dug wells have their bottom surfacebelow the ground water table.Water accumulates here fromsurroundings. Water is lifted forirrigation by mechanical means,Persian wheels operated by bullocks,horses and camels.

(ii) Tube wells are dug very deep. Wateris lifted from these wells by diesel orelectricity run pun1ps. F~ ~ M,,}"

2. Tanks: These are small storage reservoirs. They store run-off water fromthe surrounding catchment areas. Small dams are constructed below thecatchment areas to regulate the flow of water for agriculture.

3. Canal sy'tem' Canals get water mostly from large rivers. Doors are fitted atthe mouth of canal joining the river to regulate the flow of water. A canalis distributed into branch canals, distributaries or fleld channels. These fieldchannels irrigate the fields. For irrigation ofvat"ious fields, a rotation system isfollowed so that each and every farmer may irrigate his field.

4. River valley system: In the western ghat mountains of South India are presentmany steep and narrow riverine valleys. In this region, rainfall is very heavyduring June to September and again in November and December. On theslopes and in the valleys, perennial crops [coconuts, supm"i (Areca nuts), coffee,rubber, tapioca, etc.] are cultivated. Rice crop is also grown in the bottom landsof tbe valleys.

5. River lift system: Water is lifted directly from the river for the irrigation ofnearby fields. It is done due to inadequate flow of water in canal or due toinsufficient release of water from the river reservoir.

FiQ 3.2 Mixed cropping

ropping Patterns

6. Sprinkler irrigation system: It is introduced in canal irrigated areas ofHaryana, Rajasthan and Madhya Pradesb. Drip irrigation system is in usein Maharasbtra, Karnataka, Andhra Pradesh, Odisba and Tamil Nadu. It isin practice with the help of Israel technical knowhow in Indian AgriculturalResearch Institute, ]\ew Delhi. They are also providing training to the peopleofvarious states. Here they are cultivating different varieties of roses, tomatoes,capsicum of yellow and red colour, gourd, etc.

Mixed Cropping

The practice of growing two or more cropsmultaneously at tbe same time is called mixed cropping·ig. 3.2). Cropping activities go on all the year round in

:ndia, if water is available for crops. In nortbern India,ere are two distinct seasons kharif Ouly to October) andhi (October to March). Crops grown between March andne are called zaid. In some parts of the cou ntry, there

_.;;-..;,v..;,e..;,m..;,en..;,l..;,in..;,F,;.:oo..;,d..;,R,;.:es;;;,ou;;;,r,;.:ce;;;,s 1..;,0..;,.1_iiii;n;;;;;liil

102

are no such distinct seasons. Crops are grown sale or mixed (mixed-cropping), orin a definite sequence (rotational cropping). The land may be occupied by one cropduring one season (mono-cropping) or by two crops (double cropping) which maybe grown in a year in sequence. More than two crops are also grown in a year

. (multiple cropping). These are intensive cropping.

Kharifcrops include rice, sorghum (kharif), bajra, maize, ragi, groundnut andcotton.

Rabi crops are wheat, sorghum (rabi) gram and pea.

Mixed cropping: Crop mixtures are widely grown, especially during kharifseason. For example, Maize + uradbean; soyabean + pigeon pea (arhar); sorghum +pigeon pea, pigeon pea + mungbean, cotton + mungbean and groundnut + sunflower.

During rabi season, especially in unirrigated area, wheat and barley, and wheatand gram, or wheat + barley + gram are the mixtures of grain crops. Brassica(mustard) and safflower are grown mixed with gram or even with wheat. Mixedcropping is an efficient way of using land. Breeders are developing plant types inpulses and oil seeds, with good compatibility with row crops.

Choosing a mix crop: In mixed cropping, the following factors are to be keptin mind:

1. Nutritional demand should be different for both the crops. In case of wheat +gram, the latter provides nitrogen to the soil.

2. Water requirement of both the crops should be different. One needs morewater than the other.

3. Duration of both the crops should be different, one of long duration and theother of short duration.

4. Root growth of both the crops should be different, one deep-rooted and theother not, so that they may get water and nutrients from different levels.

5. Size of the plants should also be different. If one crop is tall, the other shouldbe dwarf. In this way, both the crops will get proper light, water and nutrients.

Advantages of Mixed Cropping

1. No crop failure: If one grows two crops at the same time in a field, havingdifferent requirements of nutrients and water, then harvesting of both thecrops cannot be damaged or failed due to uncertain monsoon. One willdefinitely give a good yield.

2. Improves soil fertility: Usually cereal crops and leguminous crops are grownin mixed cropping. Leguminous crops provide nitrogen to the soil becausetheir roots possess nitrogen fixing bacteria, while cereal crop depletes morenutrients. Thus, soil fertility is improved in mixed cropping.

3. Increase crop yield: Due to increased soil fertility, yield of both the crops isalso increased.

4. Variety of produce is also increased due to mixed cropping. One gets fodder,pulses, vegetables and fruits in practising mixed cropping. It is beneficial tothe family economonically and also to the farm animals.

5. Optimum utilisation of the field also takes place.

6. Minimize pest damage to the crops: In mixed cropping, one crop may be proneto a particular type of pest, weed or insect. But the other may not be susceptibleto that pest. Thus, in mixed cropping chances of infestations are reduced.

ow there is a need of increasing productivity per unit area and time. Thus,traditional mixed cropping has been retailored and system of intercroppinghas been introduced.


103 1i'1:ffi11ti1J 'J 11'l"I~

Fig. 3.4 InlercroDping of grOlmdnulsunnower

Fig. 3.3 Inlercropping pattern

I. ... 7 ........ , ~

Fertiliser can be applied according tothe need of crops sown in rows.

There is a definite pattern of rows ofcrops.

Use of pesticide to an individual cropis possible.

Harvesting of both crops at differenttimes is possible.

Marketing and consumption of thecrops can be done independently.

Use of pesticides for pest control toan individual crop is not possible.

Harvesting of both crops separatelyis not possible.

Marketing and consumption ofbothcrops can be done at a time.

I. I It minimizes the risk of failure of Increases productivity per unit area ofboth the crops. the field.

Seeds of both the crops are mixed Seeds of two crops are not mixed.before sowing.

Fertiliser to individual crop cannotbe applied.

No definite pattern of crop rows.

7.

4.

2.

6.

5.

3.

S.No. ' Mixed cropping Intercropping

I Multiple Cropping

Multiple cropping is getting more than two crops in a year in the same field.These intensive croppings (mixed cropping, intercropping and multiple cropping)may be done either in sequence or even there may be relay cropping-one cropundersown in a standing crop. Multiple cropping helps in the improvement of soilfertility. In mixed cropping, better crops having fertility in short duration are to beselected. This practice saves the time and labour of the farmers, cotton crop andgroundnut crop are grown at the same time. Proper irrigation is also required inmultiple cropping.

Future of cropping pattern: With the increase in population, the irrigatedarea is incr!,asing and with advances in agricultural science, most of the extensivecropping patterns are giving way to intensive cropping. The development in minorirrigation works has especially provided the farmers with opportunities to crop theirland all the year round with high-yielding varieties. This intensive cropping willrequire an easy and ready availability of balanced fertilisers and plant protectionchemicals. There should be an appropriate price policy for inputs and agriculturalproduce.

In India the size of the land holdings will diminish further in future due topopulation increase. Hence, the country has to produce enough for its peoplewithout deteriorating the quality of the environment.

provemenl in Food Resources

Table 3.7 Comparison between Mixed Cropping and Intercropping

I Intercropping

It is different from the mixed cropping pattern, buthere also two or more crops are grown together. Two ormore crops are grown in the field in definite separate rows(Fig. 3.3). The combination of crops is like that of mixedcropping. Here row pattern of crops is definite, with onerow of main crop, one, two or three rows of intercrops aregrown (I : I; I : 2; I : 3 or I : 4). In intercropping, withwide-rowed slow-growing crops, companion crops may begrown in rows. In case of plantation crops, intercroppingwith pulses and fodder crops is common. Chillies arerotated withjowar, whereas onion, coriander, turmeric andginger are grown as mixed crops with other seasonal crops.

Crop RotationCrops are grown in a definite sequence in a year, such

as cereal (wheat, barley) crop, and legume (pulse) cropalternately. Roots of the leguminous plants possess nodulesin which nitrogen-fixing bacteria Rhizobiulll lives. Theyfix the atmospheric nitrogen and thus, maintain the soilfertility. It increases the crop yield and also helps to controldiseases. Nitrogen is essential for the plant growth. Hence, theleguminous crops are sown in the field every year. This practiceofgrowing two different crops in a field in a year in successionis very common among Indian farmers. For example, pulses,beans and groundnuts are alternately grown between wheat,maize, bajra crops. Peas and grams are grown along withwheat in the same season. Alier harvesting peas and grams,maize or bajra are sown. Pea and gram crop enrich the soilnitrogen. This agricultural practice helps in more yield of dlecrops. Nitrogenous fertilisers are thus, less used.

Types of crop rotation Crops in Rotation

l. One year rotation I. Maize (khari!) - Wheat (rabi).

2. Maize - mustard.

3. Rice - wheat.

2. Two years rotation 1. Maize - mustard - sugarcane - 11lelhi (Fenugreek).

2. Maize - potato - sugarcane - peas.

3. Rice - pea - rice - gram.

3. Three years rotation 1. Rice - wheat - mustard - muong - sugarcane - berseem.

2. Cotton - oat - sugarcane - pea - maize - wheat.

I 3. Maize - potato - sugarcane - green manure.

Selection of Crops for Rotation

For selecting the crops for rotation, the following points are to be considered:

1. Availability of soil moisture: It may be through rain, or through irrigation.For example: Rice is an ideal crop for areas likely to be flooded heavily by rainsor by seasonally flowing river water. Wheat is grown in rabi season when theamount of rainfall is low, and it is necessary to irrigate the crop for getting agood yield. Dwarfvarieties of wheat need more water (irrigation) than the tallvarieties. Barley is similar to wheat but it can withstand more draught because


I Rotation of Crops

1. Rabi wheat is followed by crops such as maize, jowar, bajra, cotton and arhar.Sometimes, some of the green manure crops such as sanai, 1IZoong, guaT, lobiaare sown immediately after kharif to enrich the soil. Gram, linseed, barley andmustard are also included in rotations.

2. Maize (kharif crop) is a short duration crop. It is rotated with wheat, potato,barley, etc., in a one year rotation. In two years rotation, it is grown in rotationwith cotton and sugarcane.

3. Groundnut (kharifcrop) is grown year after year. In certain places, it is rotated·with wheat,jowar, bajra, gram, paddy and cotton. Groundnut in certain placesis grown mixed with jowar and bajra.

Table 3.8 Three Types of Crop Rot"tion on the b<.sis " uration

F19 35 Crop -

104....,'oJ.,._-

provement in Food Resources

Cost-benefit ratio: Return per rupee invested = fl..Test cost 0 cu tlvauon

~!.r-,'"105

of crop rotation IS

Gross return

Efficiency =

Monetary input and output relationship: Efficiencydescribed as an output per unit of input.

Output in terms of money

Input in terms of money

of its deeper and well-proliferated root system. Maize is very sensitive to excesswater. Submergence of soil for 3 to 4 days during vegetative or floweringperiod can reduce the yield up to 50 per cent. Millets (sorghum, etc.) are thehardest among cereals. They are grown in rain fed conditions. Crop should beirrigated at least at the critical stages to maintain optimum moisture in the rootzone during dry spells. Pulses are also grown under rainfed conditions andrarely receive irrigation. Oil seeds like groundnut, sesamum and niger (kharifcrop), and samowel~ mustard, castor and linseed (rabi crop) are generallygrown in rainfed conditions. Kharif seeds need one or two irrigations but rabiseeds require more irrigations during the growth period, cotton also needsless irrigation.

_ Nutrient status oflhe soil: Crops of the same family should not be repeatedlygrown in the same field year after year. It reduces some particular soilnutrients, thus depleting the soil fertility. This will also encourage the build upof diseases and insect pests.

~ v..i1abi.. nputs: Inputs are fertiliser and manures pesticides, implementsand manpower, etc. More than twO crops should be grown in a year in aparticular field. It will not deplete the soil nutrient, instead will add somenutrients to the soil. High input crops like sugarcane, potato, maize, wheatand rice may be grown before low input crop. This will maintain the fertilityof the land.

4. Crops of short and long duration should be selected.5. Marketing ofproduce: Farmer of the nearby town should grow seasonal flower

and early vegetable for getting a good price of their product. Old traditionalfarming is less productive.

Processinv 0 lrod"ce is more beneficial than the traditional marketing ofproduce.

Assessment of Crop Rotation

Selection of crops for rotation can be determined by comparing theproductivity of crops, which use similar resources (fertilisers, manures and water)and give similar produce. For example, if we grow only cereals like wheat and riceor only pulses like umd, bean, aT/wI", lIloong and gram (chick pea), and use sameinputs like fertilisers, water, pesticides, etc., the assessment can be done on the basisof the total produce and the amount of used inputs. But, if crop rotation system isfollowed, different crops are grown in the same field in a year, then the assessmentwill be different. It will be as follows:

Cropping index: It is represented in percentage.

Number of cropsCropping index = x 100

Number of years

Net returns: The monetary difference of input and output value is expressed as:

Net returns = Monetary gross return - Total cost of cultivation.

..... /.--......,. "

• Animals, especinllyi'nsects, that causedamage to crops arecalled pests.

• The chemicals whichau used to killinsects are calledinsecticides.

106

Advantages of Crop Rotation

1. It improve the fertility of the soil. In crop rotation, cereals like wheat, maize,bajra, jowar are alternately grown with legume crops (pulses, peas, grams,beans, groundnuts, etc.), non-leguminous crops alternate with leguminouscrops in the same field. Cereal crops utilise soil nitrogen for their growth,making the soil nitrogen deficient. When leguminous crops are sown in thesame field they enrich the soil with nitrogen by fixing atmospheric nitrogen.Thus, the deficient soil from nitrogen again becomes enriched with nitrogen.This cycle goes on. This increase the productivity of the crop.

2. Productivity of foodgrains thus increases.

3. Saving of nitrogenous fertilisers, because nitrogen is provided by theleguminous crops.

4. It also helps in controlling weeds and pests.

Crop ProtectionFields are infested with a variety of organisms that destroy the crops and cause

great economic loss. These are called pests. They include weeds, microbes, fungi,insects, rodents, etc. Crops have to be protected from pests by using pesticidesand herbicides. Crops also need to be saved from diseases by treating them withmedicines. Even after harvesting, the seeds need to be stored properly and protectedfrom damage. Crop protection deals with all this.

Crop protection is a technique of protecting and growing crops and preservingagricultural products from natural enemies like insects and weeds, etc. A numberof animals are attracted towards crop plants for food, shelter and breeding andcause harm to them. These animals are called pests. Pests are destructive organismscausing great harm to the standing crop in the field and also in storage. Thesepests are insects, mites, nematodes, rodents, birds, bacteria, viruses and fungi. Theassociation of pests to the crops, plants, etc., is very intimate. It is not possible toeliminate these enemies completely, but we can minimise their effect to a greaterextent by using pesticides (biocides). Crop protection is also called pest control.Pests cause direct damage to the plants.

Loss offoodgrains due to pests is about 30 per cent throughout the world. InIndia, the damage to the crop yield due to pests and diseases is about 20 per cent.Insects destroy annually about 15 per cent ofthe food produced in India.

Pesticides used to control or eliminate the pests include insecticide for killinginsects, weedicides for eliminating the weeds and fungicides for killing the fungi.

Pesticides are either sprayed on crop plants or used for treating seeds and soil.These pesticides on the other hand cause pollution of air and water if used in excess.It is easier and more effective to prevent a pest invasion by suitable preventivemeasures than to cure it, when it has attacked on the crop. The preventive measuresagainst the pests are:

(i) Use of resistant varieties of crop plants.(ii) Treatment of plants with a chemical, capable of protecting them from attacks.

(iii) Control of parasites on seed and in soil before planting.

(iv) Treatment of vectors of infection.(v) Control by altering agricultural practices, viz., crop rotation, deep ploughing,

changing cultivation seasons, etc. These are curative methods.(vi) Biological control of the pests by organisms is dangerous to the concerned

pest. Such organisms are called parasites.

Improvemenl in Food Resources

Warm and humid climate is supposed to be more favourable for infestationof insect pests. For example, maize, jowar, bajra, cotton, etc. are grown before therainy season in June and hence are more prone to insect pests and diseases than thewheat, gram, pea, etc.

1. Insect Pest Control

A number of insects are serious pests of crop plants. They do harm the plantsat all stages, all parts and products of plants. They cut roots, stems and leaves; suckcell sap from various parts of plants and bore into stem and fruits. They cause heavyeconomic loss to the farmers. Insects causing direct loss to plant are:

107

Pyrilla(sugarcane leaf hopper)

Sugarcanetop-borer

Painted bug

~~Q

Fig, 3.6 Afew common Insect pests of crop plants

Sugarcanestem-borer

Mustard aphid

.---

IGundhi bug

rovement in Food Resources

(1) Leaf eaters (defoliators): These insects possess biting and chewing typeof mouth parts. They sometimes cause serious damage to the crop, e.g.,grasshoppers, locusts, beetles, weevils and larval stages (caterpillars) orbutterflies and moths.

(2) Leaf miners: They live in between the upper and lower epidermis of leavesand eat the green parts of leaves, e.g., citrus leaf miner.

(3) Leaf rollers: Caterpillars feed upon the leaves and roll up the leaves. Theseleaves later shrivel and fall off, e.g., cotton leaf roller.

(4) Stem and root borers: Caterpillars of some insect pests bore the stems androots of various crop plants and cause serious damages. They cause stuntedgrowth and infested plants also dry up, e.g., rice stem borers and sugarcaneborers.

(5) Sap suckers: Some insect pests have piercing and sucking type of mouth parts.They suck the juice of plants. The extraction of sap or juice of plants causesevere damage to plants. Leaves become brown and fall. off, e.g., rice gundhibug, mustard aphids, etc.

(6) Bark and wood feeders: Beetles and weevils make tunnels in the bark andwood of trees and shrubs, e.g., bark eating caterpillar and termites.

(7) Fruitdestroyers: They attack fruits, making them unfit for human consumptionand seed purposes, e.g., fruit flies attack fruits of cucumbers, mango, guava,etc.

(8) Seed feeders (storage insects): Certain insects like rice weevil, rice and flourmoth, potato tuber moth, etc., damage the stored grains, etc.

Insects causing indirect losses to plants: Most aphids and leaf-hoppers secretehoney dew on their host leaves, It causes the development of sooty moulds whichchecks the growth and development of plants, Blight, mould and wilt diseases arecaused by fungus, bacteria and virus, These diseases are transmitted by sap suckinginsects, Viral diseases ofpotato, tobacco, peach, etc., are transmitted by leafhoppers,aphids, etc.

Control of Various Insect Pests

(i) Control of root cutting types of insects is done by mixing insecticides in soil,e.g" chlorop\Tiphos,

(ii) Control of leaf and stem cutting and boring type of insects is done by sprayingor dusting the contact insecticides. These penetrate the exoskeleton of insectsand kill them, e,g" lindane, thiodon and malathion.

(iii) Control of sap-SUCking insects (e,g., aphids) is done by spraying of dimethoate,metasystox, etc. These are systemic insecticides, absorbed into the' tissuesof plants, and when an insect sucks the sap, it enters its digestive system,killing the insect pests, Such insecticides are required in less amounts forsprayll1g,Pathogens are always present in the environment and when they get favourableconditions for their growth, they infect the plants, These pathogens aretransmitted through the soil and seed, water and air. Soil, water and seedborne diseases mostly infect roots and stems, whereas air borne diseases attackthe aerial parts of plants, Soil and seed borne diseases can be controlled bytreating soil and seed, Air borne diseases are controlled by spraying fungicidesolution on infested parts of plants.

Precautions

All pesticides should be used according to therecommended dose, At the time of use, instructions writtenon the packet should strictly be followed. It may cause harmto the human beings and livestock,

Pesticides should be kept well packed and awayfrom the reach of children, Person spraying pesticideson crops should keep his mouth and nose covered, Avoiddirect contact with pesticides; it may be harmful to humanbeings.

I 2. Biological Methods of Pest Control

It includes deliberate introduction of living material(parasite, predator or pathogen or an animal pest) into theenvironment of the pest so that its population density maybe reduced or damaged. The living material is a naturalenemy of the pest.

For example, ladybird beetles and praying mantisdevour the scale insects and aphids, feeding on plant sap,Insect pests are also controlled by bacteria called Bacilluslhuringiensis, These bacteria enter the body of insect pest,multiply and kill them,

~""./',,----

Fig. 3.8 Rust disease of wheat

108 Improvement in food Resources

Table 3.9 Control Measures of Insect Pests of Major Crops

S. I Name Name of insect pests Nature ! Controlof the I Common Scientific I of

No. measurescrop name name damage

I. Rice (Oryza I. 1. Gundhi Leplocorisa INymphs and adults suck II. Plough the land immediatelysativa) bug vancorrus the sap of tender grains. after hanest and destroy

Affected earheads stand stubble.erect like normal ones, 2. Spray with Manacrataphas atbut without any grain the rate of 0.5 kg/hectare orformation. Attack is during 0.04%post-flowering time. Diazinon or Phosphamidon or

Fcnitrothion.

2. Leaf TeUigella Both nymphs and adults Spray ~10nocrotophosat the ratehopper spectra suck sap from young leaves. of 0.5 kg/hectare or Spray 0.4%

Infested leaves turn yellow. Phosphamidon or Diazinon.

2. Wheat I. Gujhia Tanynecus Grubs feed on roots and Mix 5%, Aldrin dust in the soil(Triticum weevil indicus adults cut the growing before sowing at the rate of 20 kg/

I

aesitivu:m) points. hectare. For adults, dust 5% BHC.

I

2. Shoot fly Atherigona Maggots attack seedlings Application of 10% Phoratc ornaqvn and kill the central shoots, Disulfoton (5%) to the soil at the

causing dead hearts. time of sowing.

3. Sugarcane I. Top TfJporhyza Larvae bore into the midrib Apply I kg of Phorate granules at(Saccharum borer nivella of leaves, make tunnels the rate of 20 kg/ hectare at theofficinarum) enter into the growing base of shoot in June. Also spray

point and damage it. 0.05% \lonocrotophos.

2. Shoot Chilo Larvae bore into the central Apply Lindane 51 kg/hectare inborer infuscatellus shoot and make tunnel 800-1000 litre water in furrows

downward. Larvae feed before planting.inside on the soft tissues.

3. Leaf Pyrilla Both nymphs and adults Spray Endosulphan 35G at the ratehoppers perpusilla suck sap from underside of of 1.251 kg/hectare. Dust 5% BHC(pyrilla) leaf. or spray 0.03% \lonocrotophos.

4. Chickpea Pod borer Heliothis Sps. Larvae first feed on tender Spray Carbanl at the rate of 1.5(gram) leaves. Later on, they make kg/hectare.

holes in pods and feed thedeveloping grain.

5. Groundnut White grub Laclmosterna Grubs feed on roots and Apply 10% Phorate granules.(Amchis consangumea kill plants.

I

hypogaea) Adult beetles feed on Application of Thimet 10 Gleaves. granules at the rate of 20 kg per

hectare before sowing.

6. ~1ustard \1ustard Lipaphis Nymphs and adults suck Spray 0.5% Lindane, or 0.02%(Brassica aphid e'JSl11u sap from the leaves and Phosphamidon or Spraycampestris) other tender parts of metas\Stox 25 EC at the rate of 11,

plants. kglhectare in 1000 litre water.

Affected leaves get curled Dusting with 5% Malathion at theand plants wither and die. rate of 20 kg! hectare, or Dust

5-10% BHC or 4% Carbaryl.

Painted Bagmda Both nymphs and adultsbug cnlciferarum suck the sap of leaves at the

i seedling stage and devitalizeI plants.

.' _'ovement in Food Resources 109~ / .•

Fog 3.9Tikka disease of groundnut

Crop DiseasesDiseases produce disorders in the body due to harmful physiological changes.

The causative agents like bacteria, virus and fungus change the normal physiologicalprocess. Thus, certain distinct symptoms appear. Diseases cause the loss of amountof plant products in the field and also in store. Plant diseases have been classifiedinto the following three categories:

(1) Soil borne diseases: Their pathogens are found in the soil and underfavourable conditions the pathogens infect the roots either at a seedling oran adult stage of the plant. Examples are smut of bajra, tikka of groundnut.(Fig. 3.9).

(2) Air-borne diseases: Their pathogens (fungi) are found in the air. They infectthe aerial parts ofthe plants, e.g., shooLS, leaf, flower and fruits. Examples arerust of wheat, rust of gram, blast of rice, mildews, etc.

(3) Seed-borne diseases: Some pathogens (fungi) live dormant in the seeds andother propagative organs of the host plants. These dormant pathogens becomeactive when infected seeds germinate and cause infection, e.g., ergot of bajra(pearl millet), leaf spot of rice, loose smut of wheal, covered smut of barley.

(4) Water-borne diseases are transmitted through water, e.g., blight of rice(bacterial).

I Control of Plant Diseases

Control of plant diseases is necessary to prevent the quality and quantity ofyield. Import only disease free seeds and propagative parts. Many pathogenic fungicomplete their life cycles in two hosts. Alternate host provides shelter to the pathogenunder unfavourable conditions, destroy this alternate host so that the pathogen'slife cycle does not complete. By crop rotation pathogens can also be minimised ordestroyed because then they will not get an alternate host for completing their lifecycle. Compounds of sulphur, mercury, arsenic, zinc and copper are also used tocontrol plant diseases.

Table 3.10 Important Diseases of Major Crops and their Control Measures

Diseases jName of the Symptoms Control measuresCommon Causativecrop

organismname

Rice (Oryw Blast Piricu/o,ri orywe Brown boat-shaped lesions on Treat seed with thiram solutionsativa) leaves, stem and grains. in water (2.5 g/kg seed ). Spray

Bavistin (l gil water) at 10 daysinterval. Treat seeds with AgrosanG'\ (2.5 g/kg) before sowing.

Bacterial Xanthomonas Watery yellow lesions with Grow tolerant varieties of riceblast orywe brown margins on leaves. like IR-20 and Pusa 2-21. Treat

Later the whole plant may seed with mixed solution ofappear blighted. Streplocycline (0.015%) and

wettable ceresan (0.05 %).

Wheat Rust Puccinia Brown rust-colour elongated Spray Dithane M45 at 2g/1 water at(Triticum grmmmntS SpOLS on leaves and stem. 10 days intervals.aestivum) Grains develop black powdery

smut in them.

Sugarcane Red rot Colletotrichwn Small red spots on leaf mid Grow resistant varieties. Treat(Saccharum falcatU1n rib appear. Leaves wither. Pith seeds with Areton or Agalloofficinarum) of sugarcane turns reddish. (0.25%) for 5 min before sowing.

./.~--"

110 Improvement in Food Resources

L"-- _

I Gra"y Mycoplasma 1'roduction of many thin Treat seeds with hot air at 54'C forshoot tillers from the base. S hours. Use healthy seeds.

Sprouting of lateral buds.

Chickpea Wilt Fusarium Leaves become yellow and Deep sowing at 8-10 em depth in(gram) oxysponL1n dry up. Roots turn black and the light soil.

decompose.

Pigeon pea Stem rot Diplodia cajani Development of dark brown Mixed cropping of sorghum andlesions on stem near the soil chickpea. Avoid water logging.surface. Girdling of stemleading to death of the plant.

Groundnut Tikka or Mycosphae,~lla Light brown oval-shaped Spray Bavistin (0.05 %) at 15 days, (Arachis leaf spot berkeleyii and lesions on leaflets, petiole and intervals. Grow resistant varieties.

hypogaea) Mycosphae-rella stem.arachidicola

~ustard 'Vhite rust Albugo candida Cream yellow or white pustule Spray Dithane Z-7S or Dithane(Brassica on the lower surface ofleaves. M45 at 2g/1 in water. Removecampestris) and burn affected plant

debris.

Downy Peronospom Yellow irregular spots on Remove and burn affected plantmildew brassicae. leaves. Inflorescense is debris. Spray the crop with 0.2%

malformed, twisted and bent Ziram or l\laneb.with 'white powder in severeinfections.

Weed Control in the Fields

Along with the crop plants, certain unwanted plants also grow in the fields.These unwanted plants are called weeds. These weeds adversely affect the growthof the crop plants, since they also absorb soil nutrients, water, fertiliser and manure,and take sunlight for photosynthesis. This causes decrease in growth of crop plantsand their yield. Hence, their removal is essential. Weeds may act as an alternate hostfor certain microorganisms and insects and pests, which develop on them. Theselater attack on crop plants affecting their growth and yield. Some weeds produceubstances which may be toxic to crop plants, inhibiting their growth. Seeds ofweeds

may also be harmful to human beings when mixed with seeds ofcrop plants. Say, forexample khesari dal produced along with arhaT dal in Madhya Pradesh is poisonousor human beings.

1. Common Weeds

Weeds share the same habitat. In some cases weeds may be a crop plant another~owing with crop, such as mustard plants in wheat crop. But they are sown along,;th wheat in a separate line on an elevation. Wheat plants of C-306 (tall variety)e weeds in the field of wheat HD-2687 of dwarf variety. Growth of weeds is morekharif crop in comparison to rabi crops. Bathua (Chenopodium) which we eat in

-inters grows abundantly in wheat fields as a weed. Weeds in different seasons anddifferent crops vary. Amaranlhus (chaulai) is a common weed that grows with all

ops. Arge11lone with yellow flowers is also a weed.

Weeds are of two types:

(i) Broad leaved weeds, like chaulai, (Amaranthus), bathua (Chenopodium). Theseare dicotyledonous. They grow in a monocotyledonous crop such as cereals.

Ivernen! in Food Resources III VK Biology IX 1----,

(ii) Karrow leafed weeds. such as wild oat, grass, etc., are monocotyledonous.

Grass

Narrow-leaved weeds

Wild Oat

Broad-leafed weeds

Convolvulus

Table 3.11 Weeds of Different Crops

Amaranlhus viridis (Chaulai) Cyperus mtundus (nut grass, motha),TTiamhema (saathi) wild sorghum Gangli jowar)

Fg.3.10 Certain common weeds

Crops

Chenopodium

Kharif (maize, Jowar,bajra, pulses, rice)

Rabi (wheat, barley, Chenopodium album (bathua) PhalQ17s (mandoosi), wild oat Ganglipea, gram, etc.) Convolvulus (hirankhuri) jari)

I 2. Weed Control Methods

Removal of weed plants from a crop field is called weeding. Weeds can becontrolled mechanically, chemicaJly and biologically.

(i) Mechanical methods: Weeds are removed by picking them manually or byharrow, ploughing, and tilling, mowing or cutting with machines.

(ii) Chemical methods: Weeds are also destroyed with the help of weedicidesor herbicides. Herbicides are applied to the foliage of weed or to the soilthree times: pre-planting of crop; after planting, but before emergence; afteremergence. They may damage the weed either by contact with the roots orwith foliage or after translocation through the roots or through the foliage.Herbicides (inorganic) are sulphuric acid, obtained as Bov-brown oil ofvitriol,sodium chlorate, borax, and crude sodium borate. Organic herbicides areauxin-type growth regulator. MCPA, 2 methyl-4-chlorophenoxyacetic acidand 2, 4-dichloro-phenoxyacetic acid kill many annual and perennial weedsin cereals without damaging the crop.

(iii) Biological methods: Control of weeds is done by using insects which feedselectively on a particular weed. Certain microorganisms are also used to killthe weeds by producing disease. Cochineal insect control the growth of pricklypear weed (Opuntia). Control of aquatic weeds is done by growing fish, likegrass carp. Millet, barley, soyabean, etc., crop plants do not allow the growthof weeds. These crops are called smoother crops.

(iI') Cultural methods: Prepare proper seed bed, crops should be sown at propertime, crop rotation and intercropping are beneficial to control weeds.

Amaranthus

.../ ..,---. "

VK Biology IX 112 Improvement in Food Resources

VK Biology IX113

Rust red flour beetle

Khapra beetle

S O'M gra nt

\.

Rice weevil

Lesser grain borer Grain and flour moth

Pulse beetle

Rice moth

(2) Abiotic factors

Moisture or humidity and temperature are the abiotic factors.


Food grains are stored in silos (FCI, Food Corporation of India) and also ingunny bags in large store houses by FCI and also by traders. Farmers also storewheat in gunny bags in large rooms along with wheat plants husk (bhoosa). Duringthe storage of food grains damage occurs mainly by two factors:

These include insects, rodents (e.g., house rat and mouse, and squirrel, etc.),birds, mites, bacteria and fungi. Birds like parrot, parakeet, pigeon, bulbul, etc.damage the standing mature crop. A few insect pests of stored grains are:

(i) Grubs of Pulse beetle or gram dhora (Callosobruchus maculatus) damage storedgrams.

(ii) Grubs and adult beetle of rice weevil (Sitophilus oryza) damage rice. Larvae ofrice moth (Corcyra cephalonica) damage rice and maize.

(iii) Wheat weevil or Khapra (7i·ogodenlla granariwm) damage wheat grains.(iv) Caterpillars of grain and flour moth (Sitotmga ccrealela) bore into grains of

wheat, rice, barley, maize and jowar.

(v) Adult and larvae of rust red flour beetle (7iibolium castanewn) damage wheatflour.

(vi) Grub and adult beetle of lesser grain borer (Rhiwpcrtlza dominica) damagegrains, feeding on inner material.

I (1) Biotic Factors

Scientific Storage of Food GrainsIt is very important to preserve the stored food grains from losses due to

insect pests, other pests, fungi, etc. Food grains are stored either for future humanconsumption or for seed purposes. Improper storage conditions cause insectinfestation. Deterioration in quality and quantity of food grains also occur due toimproper storage of food grains. About 100 crores loss occurs annually in storedagricultural produce, i.e., about 9.3% annual loss. Beetles and moths are importantpests of stored grains. In case of beetles, grubs and adults, both attack the storedgrains, while in case of moths, only caterpillars damage the food grains.

Fig, 3.12 Penicillium

Fig. 313 Yeast

Temperature

Maximum growth ofinsects occur at 30°C to 32°C temperature. Microorganismsbecome active at 30°C to 40°C. The food grains, thus, should be stored below 30°C,at which microorganisms and insects remain less active, causing less damage.Vegetables and fruits require 1°C to 7°C for preservation. Meat and fish are storedat 3°C to 8°C and 7°C to 10°C respectively.

Moisture

Food grains should be dried before storage. Moisture content of grains shouldnot be above 14 per cent by weight. Moisture above this level causes decay to grainsby helping in the growth of microorganisms and insects. Microorganisms and insectsrelease heat during respiration, which cause a rise in temperature ofthe space. Thisheat is called dry heat.

Humidity

Humidity in air promotes growth of moulds like MUCOT or Penicillium overthe grains. These cause decay of grains. Therefore the storage houses should alsobe dried before storage. Humidity more than 14 per cent also cause germinationof grains leading to rise of temperature. This rise of temperature of food grainsdue to growth of fungus and germination of seeds due to more humidity is calledwet heating or damp-grain heating. Both dry heating and wet heating reduce thequality of stored grains. They also affect the germination of seeds.

Thus, biotic and abiotic factors cause infestation of insects, degradation ofgrains in quality, weight and germination, etc. Such crop produce fetch low marketprice causing economic loss.

I Preventive Measures before Food Grain Storage

The following preventive measures should be taken before storage of foodgrains in storage houses:

(I) Drying: The moisture content of crops at the harvest time ranges from 15to 35 per cent. Grains also absorb moisture from the atmosphere, if humidconditions of the environment prevails. The moisture content in grains shouldbe below 9 per cent. If it is above this prescribed limit, it will cause decay offood grains by microorganisms (e.g., bacteria, fungi) and insects. Therefore,the food grain crop should be dried first in the sun and then in shade. Fordrying, it should be spread thinly on the cement floor. Mechanical driers arealso used for drying on a commercial scale. They blow hot air. Removal offoreign particles from food grains, such as weed seeds, earth particles, stonepieces, straw, etc., is also essential before storage. Thus, crop of food grainsshould be well sieved.

(2) Maintenance of hygiene of store houses: Storage places like warehouses, binsand godowns should be clean. They should be devoid of dust, dirt, rubbish,webbing or refuse of previous grains. The cracks and holes in the walls, floorand ceiling should be sealed by cement. Gunny bags used for storage of foodgrains should be new. If old gunny bags are to be used, they should be turnedinside out and then dried in the sun and fumigated or sprayed by insecticidesand fungicides. If any moisture persists in the bags or any' fungal infection ispresent, it will damage the grains. Earthen pots (matka, etc.) used in villagesshould also be dried and cleaned. Food grains should also be dry, cool andclean. Mouths ofgunny bags after filling the grains should be stitched properly.The grainfilled gunny bags should be stored in store houses in tiers, oneabove the other and there should be space in between tiers for inspection and

:.-----. \ VK Biology IX 114 Improvement in Food Resources

Malathion (50 EC):

Pyrethrum (2.5 EC):

,

VK Biology IX115

13010 m2 area in I : 300 dilution.

13010 m2 area in I : 300 dilution.

(2) Fumigation: In fumigation, the solution of pesticides is converted into fumes(vapours). Fumigants should be toKic to insects and mites. It should penetratethe material to be protected easily and it should not damage the material orleave harmful residues. It should not be phytotoxic. Fumigants enter the pests'body through spiracle. Fumigants are most-effective in closed spaces. They arewidely used for the control of stored-product pests.


fumigation if needed. Gunny bags should not touch the side walls, otherwisethey may get moisture. Storage places should also be dried before storage.

(3) Prophylactic treatment: Storage places should be sprayed with insecticides,fungicides, etc. or fumigated for making them free from microorganisms andpests. If the grains are used for sowing, they should be mixed with properinsecticides and fungicides. Gunny bags, especially the old ones, may also befumigated or treated with pesticides before fIlling grains.

(4) Improved structures for storage: For safe storage of grains improved storagestructures should be used, such as pusa bin, pusa cubicle, pusa kothar and pantkuthala. These structures are air tight, moisture proof, thermally insulatedand rodent proof. •

(5) Silos: These are used for large scalestorage of grains. These are largeand tall cylindrical steel structures,having outlets (chutes) at differentlevels to withdraw the stock of grainswhen required. They are built-inarrangements for temperature control,aeration and fumigation, etc. Theyare all proof, i.e., insects, birds andmammals cannot damage the grains.In silos large quantity of grains can bestored. Gunny bags are not required insilos. Silos are located in Hapm (UttarPradesh).

BHC WP (50 per cent): 13010 m2 area in 1 : 25 dilution.

Control Measures against Pests Fig 314 Agrain·silo

Grains stored for human or animal consumption should not be mixed withany type of pesticides, but they may be fumigated. Seeds for sowing purpose canbe mixed with pesticides for keeping them free from every type of infestation. Pestinfestation of stored grains can be avoided by the following techniques:

(I) Chemical control by insecticides: Insecticides are sprayed or dusted on storedgrams.

Spraying of insecticide solution is done by manual sprayer or mechanicalsprayer. In this method, only surface layer ofgrains get sprayed. Gammaxene orbenzene hexachloride wettable powder (BHC WP), pyrethrum and malathionare used for spraying the storage places at 3 weeks' intervals. Preparation ofspray solutions are as follows:

,.,t'·....·~----VK Biology IX 116

The following are the chieffumigants:

(i) Carbon disulphide used on grains.

(ii) Ethylene oxide used on grains, cereals and some plant products. It is alsotoxic to some bacteria, viruses and fungi.

(iii) Aluminium phosphide (AlP) tablets (black poison), each is of 3 grams.These are used at the rate of 2 tablets per tonne grain or 160 tablets percubic metre volume of grain.

(iv) 3 : I mixture of Ethylene dichloride plus carbon tetrachloride (EDCT) inliquid form is used at the rate of 30 mU I00 kg grain.

(v) Ethyle dibromide (EDB) in liquid form is used at the rate of 3 mL for onequintal (100 kg) wheat. It is available in glass ampoules ofdifferent capacities.

These are found wrapped in clothes. It is inserted deep in the storagegrains and is broken. It is gradually converted into fumes into the grains.Storage place should be sealed for good results.

(vi) Methyl bromide at 16 g per cubic metre is also used.

(3) Plant products: Grains of legumes are protected from insects by smearingthe grains with a small quantity of vegetable oil or mineral oil. This practice isvery old and used in villages. Cowdung burnt hot ash is also mixed with grainsof legumes to protect them from pest attacks. Such treatment prevents egglaying, reduction in egg hatching, interferes in larval development, i.e., veryfew hatch as adults. Control of insects is also done by mixing of neem kernelpowder and crushed dried fruit of black pepper.

I Precautions for Handling Pesticides

Pesticides are poisonous to some extent to human beings, domestic animalslike dogs, cats, cows, etc. Therefore, they should be stored carefully beyond thereach of children. Their application also need precaution-nose and mouth shouldbe covered with a cloth, gloves should be used, etc. Also dispose off the leftoverscarefully.

FOOD RESOURCES: ANIMALS

Since ancient days, man has beendependent on animals for food and clothing.The primitive men obtained animal food mainlyby hunting them. Later he domesticated animalsfor milk, meat, eggs and fur. These animals werecow, buffalo, sheep, goat, pig, horse, donkey,camel, mule and hen, etc. These animals werecalled domestic animals and when he starteddoing agriculture, he took the help of bullocksfor ploughing the fields, pulling carts andcarrying loads. Cows provided milk. Cows wereworshipped since time immemorial only becauseboth their progenies-males and females were ofimmense use to man. Nowadays in machine age,bullocks are replaced by tractors. ow male andfemale buffaloes are in use, females for milk andmales for carrying loads and pulling carts.


Now a special branch of agriculture has been developed for feeding, rearing,improving animal breeds. This is called Animal Husbandr~.

The term livestock is used for cow, buffalo, sheep, goat and pig, etc., which areraised on a farm. Animal food is rich in proteins. Y1i1k is a nutritious food rich inproteins, carbohydrates (lactose sugar), fats, vitamin A and 0, minerals (phosphorus,calcium) and water (90%). Fish meat is also rich in protein, fat, vitamin A and D.Animals, insects providing food can be divided into following categories:

(l) Milk-yielding animals like cow, buffalo, sheep and goat. These animals arecalled milch animals.

(2) Meat and egg-yielding animals, like hen (poultry), duck, goat and fish provideeggs and meat.

(3) Honey yielding insects like bees (apiculture), for providing honey, wax, etc.

Table 3.12 l\;utritional T alue of Various Animal Products(Amount of . 'utrients in Percentage)

• Animal husbandryincludes rearing,feeding andimproving theirbluds.

IS. No. Animal Fat Protein Carbohydrate Minerals Waterproducts (Sugar)

I I. 'Cow milk I 3.60 4.00 4.5 0.70 87.20

2. ~1eat 3.60 21.10 ' Little amount 1.10 74.20

3. Fish meat 2.50 19.0 Little amount 1.30 77.20

4. Egg 12.0 13.0 Little amount 1.00 74.00

,0,

1---"-_..J

Dr. V. Kunen

117

Year Egg Fish,

Milk(crore tonnes) (in lakh tonnes) (Iakh tonnes)

1970 60 17.56 170

1980 1300 24.42 302

[990 1960 32.00 5[5

2000 3355 5656 780

Department of animal husbandry is doing an immense work in improving thebreeds of cattles (cow, sheep, goat and buffalo), pigs and poultry. It resulted in aremarkable increase of milk yield from improved breeds of cows and buffaloes, andpoultry products from poultry.

Table 3.13 Comparison in the Production of Animal Food since 1970.

The increase of egg production brought about a silver revolution in the fieldof animal husbandry. It is especially done in the states of Punjab, Haryana and UttarPradesh. Egg consumption especially in winters has also been increased in northernstates of India. Similarly, production of milk has also increased remarkably becauseof Operation Flood Programme. All this has happened due to the development ofhigh milk yielding cattles (cows and buffaloes) by the efforts of government andprivate organisations. In Maharashtra, milk yield has increased many times. MotherDairy is largely purchasing the milk from the dairy cooperative societies, whichdirectly purchase from the individual farmers.

Dr. V. Kurien, born on 26th Nov. 1921, is the founder chairman of NationalDairy, Development Board C\fDDB). He designed and implemented the 'OperationFlood', World's largest dairy development programme. Dr. Kurien is the architectof modern dairy industry and father of white revolution.


Milk Producing (Milch) Animals

Milk-producing animals are cows, buffaloes, sheep andgoats, but mainly cows and buffaloes provide almost the entiremilk to the dairy industry. Artificial feeds and nutrient foodare manufactured to improve the milk yield of cows. Themale animals (ox) are used in agriculture for labour (carryingloads) and are also for providing meat and hide. Buffalo meatis exported to Gulf countries (Saudi Arabia, etc.) in sealed tinpacks. The products produced from the milk are ghee, butterand cheese, etc. Their excreta (dung) is used as manure andalso in producing gas (gobar gas) for cooking and lightingpurposes.

Dairying is the production and marketing of milk,usually of cow and buffalo and its products (butter, paneerand ghee). Dairying includes care of cows, their breeding,feeding, management and milking. Breeding techniques andapplication of genetics in stock improvement programmes ofcattle (cows and buffaloes) has increased the production of newbreeds with high milking capacities.

I Important Breeds of Cows and Buffaloes

There are many breeds of cows and buffaloes ll1 ourcountry. Buffaloes are mainly restricted in northern statesof India. Various breeds of cows are classified into threecategories: draught, dairy and dual-purpose breeds.

I. Draught breeds: These are strong and sturdy animals used mainly as beastsof burden. These are used for drawing bullock carts, ploughing land andtransportation. Cows ofthese breeds give less milk.

2. Dairy breeds: These cows are high milk yielders but bullocks are poor fordraught purposes.

3. Dual purpose breeds: These animals serve two purposes well. The cows aregood milk yielders and bullocks are good for draught purposes.

In India (rural), cows are of various breeds-indigenous (Indian), exotic(foreign) and cross breeds for dairying. Cross breeds are developed by mating bullsof exotic breeds and cows of Indian breeds.

Fig. 3.16 Ayshire

Fig 317 Murrah buffalo

I Indigenous Dairy Breeds of Cows

These are Deoni (found in Andhra Pradesh), Gir (Native of Gujarat, mediumin size and good milk yielders), are found in Rajasthan, Maharashtra and Baroda.Red Sindhi (medium sized and red in colour with dark and light red shades) foundin Punjab, Haryana, Odisha, Karnataka, etc., Sahiwal (large and of heavy build andare superior to other breeds) found in Punjab, Tharparkar (grey Sindhi) found inRajasthan, Maharashtra and Haryana. Deoni, Tharparkar and Haryana are dualpurpose cows and are fairly good milk yielders.

Buffaloes

Indigenous breeds of buffaloes are Nagpuri, Jaffrabadi, Mili-ravi, Mahsana,Surti and Murrah. ~lurrah is the breed of Punjab and Haryana. Its average yield ofmilk is 1800 to 2500 litres with fat contents about 7 per cent. Mahsana is the breedof Gujarat (Vadodara and Mahsana districts). Their milk yield is about 1200 to 2500litres. They start giving milk at a comparatively early age.

~~''';,118 Improvement in Food Resources

Fig,3.18 Improved high milk-yielding cow (Holsteln-Frieslon)

Improved Breeds of Cows

Indigenous breeds of cows have been crossedwith the exotic breeds of bulls to produce high milkyielding cows. Exotic breeds like jersey, Brown swisshave long lactation periods, while local breeds likeRed Sindhi and Sahiwal show excellent resistanceto diseases. The tlVO are crossed to obtain offspringswith both the desired qualities. The improvedhigh-yielding breeds of cows produced in Indiaare Frieswal (crossbreed of Sahiwal and Holstein-_riesian), Karan swiss (crossbreed of swiss andahiwal), Karan-Frieswal (crossbreed ofTharparkarnd Holstein-Friesian), jersey, Holstein-Friesian

and Murrah. Lactation (milk production) period isthe period between the birth of a young one and thenext pregnancy. It usually lasts for about 300 days.Lactation period of various breeds and milk yield is given below:

Surti is also the breed from Gujarat (Districts of Vadodara and Kaira). Theiraverage milk yield is 1600 to 1800 litres with a fat content of about 8 to 12 per cent.

Exotic Breeds of Cows

Exotic breeds are those which are imported and reared in India. Exoticbreeds are crossed with indigenous breeds to obtain cross-breeds. These have good,desirable characteristics than pure indigenous forms. Imported breeds of cows areHolstein-Friesian of U.SA, jersey (U.SA), and dual purpose cow Swiss (EuropeanBrown) and Gurnsey (English).

Ftg. 3.19 Improved htgh m ,-y:eld ng cows

Table 3.14 Improved Indian Breeds and their Milk Yield

Name of Breed ' Milk Yield in litres in one Lactation PeriodLactation Period

Gir 1200-2200 320 daysRed Sindhi 700-2200 298 days

Sahiwal 1100-3100 310 days

Holstein 3200 365 days

Kanarei 1400 -Tharparkar 700-2200 -

Karan-Frieswal 3500 -

~urrah (buffalo) 2000 -

ovement in Food Resources 119

Breeds of Sheep and Goat

Sheep is largely reared by poor people. It provides milk, meat and hide. Theirexcreta is used as manure. Likewise goats are reared for milk, meat, wool and hide.These are also reared by poor people. They both need less space as shelter. Goatwool is used in making rough blankets and pullovers in rural India and in hills.

Important breeds of sheeps are Gurej, Lohi, Bikaneri, Gaddi, Rampuri,Mandya, Bhakrawali, Nellore, Marwari and Deccani.

Important breeds of goats are Jamunapari, Barbari, Bengal, Kashmiri,Marwari, Gaddi, Pashmina, Surti and Malabar.

Breeds of Poultry Birds

~"Red Jungle Fowl

Poultry includes fowls, ducks, geese, turkeys and guinea fowls. Poultry mainlydeals with fowls (hens). Poultry breeds are reared for eggs and meat. Poultry forms asubstantial source of food protein for human beings. Poultry farming is easy to startand maintain in a small space and with a little finance. It gives quick return.

Indian poultry breeds provide goodquality meat but they lay less number andsmall sized eggs. A desi hen lays about 60 eggsper year, whereas exotic breeds lay larger andmore number of eggs per year. Desi hens arecomparatively strong and immune againstdiseases in com parison to exotic hens whichrequire more protection and immunizationagainst diseases. The breeds are crossed toobtain offsprings with both the desired qualities.With the introduction of exotic breeds offowls, poultry farming has gained considerableimportance in India. It has now become popularand thousands of farms have developed inIndia, where a large number of fowls are bredand reared for egg and meat production.

White Leghorn

F~. 3.20 Poultry breeds

Grey Jungle Fowl

Barred Plymouth

Green Jungle Fowl

I Poultry breeds1. Indigenous (desi) breeds of poultry birds: These are Aseel or Indian game

(high yield of meat but not good egg layer), Basara, Chittagong, Ghagus,Brahma and Kochi. Peela (golden red), yakub (black and red), nurie (white)and kajal (black) are other Indian breeds.

2. Exotic breeds of poultry birds (hen): These are white leghorn (small bodysize, egg long and white, needs less food for maintenance), Rhode Island Red(yields good meat and fairly good egg layer), Black Minorcha, Plymouth andLight Sussex. These birds are bred and acclimatised to the local conditions.These birds were brought here by European residents. These birds lay moreeggs than the indigenous birds but give less meat.

3. Improved breeds of poultry birds: These are White leghorn, Minorcha andRhode Island Red. Other improved breeds are B-n, H 260 and IBL-80.These take less food but lay more eggs, i.e., about 200 to 300 in a year, andprovide more meat. Indigenous (desi) breeds of hens resemble the leghornbreeds in size and shape. Desi breeds are not good egg layers. The desi henis the best mother and an ideal sitter. The desi breeds are Aseel, Chittagong,Brahma and Ghagus, etc.

t ....VK BIOlogy IX 120 Improvement in Food Resources

Aseel birds are good for meat, which is plentiful, delicious and have a pleasantflavour. They are not good egg layers.

Chittagong are comparatively good egg layers. Their meat is delicious.

Ghagus are fairly good egg layers and good sitters. Its meat is delicious andused for table purposes.

The most popular exotic breeds in India are White leghorn and Rhode IslandRed. White leghorns are not good for meat purposes but are good in egg production.Rhode Island Red is good for meat and eggs. This is kept in Government poultryfarms. Its chicks grow quickly and so are reared easily.

The present day fowls reared for eggs or meat are cross breeds of Leghornsand Rhode Islands with indigenous breeds.

I Poultry feed

Feeding of poultry birds is important for rearing. The quality of food isresponsible for the growth of birds, egg-laying efficiency and quality of eggsproduced. Their diet includes adequate amount of water, carbohydrates, proteins,fats, vitamins, minerals etc. Maize, sorghum and wheat are a good source ofcarbohydrate. Groundnut cake is widely used as a protein food. Tissues of animalslike fishes, slaughter wastes and blood from slaughter houses, etc., are an idealprotein source.

I Poultry care

They should be provided good food and clean hygienic shelter. Poultry farmingneeds care for food, shelter and disease contro!' First phase oflife of poultry is thegrowing period upto sexual maturity. In this period chickens are called growers andthey require enough space for proper growth. They need restricted and calculatedfeed for normal growth.

Period from sexual maturity upto the end of egg laying is called laving periodand chickens are called layers. They also require enough space and lighting. Lightintensity and duration oflight effect the laying output of hen.

Broilers (meat yielders) are used for getting meat. They require protein richfood with adequate fat. Poultry feeds are rich in vitamin A and K. These birds shouldget good housing and environmental conditions for their fast growth and low deathrate.

I Poultry disease

Poultry birds also suffer from diseases, which may be caused by bacteria,viruses, fungi and other parasites. Over-feeding also causes sickness like cropbound, diarrhoea, dysentery, etc. Ticks also cause tick fever, feed on blood oHow!.To protect them from diseases, it is necessary to provide good food, and sheltershould be disinfected from time to time. Vaccination is also a control measure forcertain diseases.

Fish

Fish is a rich protein diet for human. Fish industry in India is about 1,500years old. Fishes provide valuable source of food supply to the inhabitants of thecountries located in tropical regions. Fish meat contains 60 to 80 per cent watel~ 13to 20 per cent protein and fat. It also contains vitamins and phosphorus. Fishes areof two types: Marine and freshwater. Both are used as food, but not all marine fishes

Improvement in Food Resources 121 VK Biology IX ---.:::,

are used as food. For fishing, our inland water area is about 1.6 million hectares andcoastal line is about 6,500 kilometres. Thus, our country has a great potential forfishing industry. Besides food, fish also provides a number of other products:

1. Fish oil: Fish liver oil is extracted from liver which is of great medicinal value.It contains vitamin A. In some fish, liver oil contains vitamin C, D and E also.Fish liver oil is extracted from cod fish, tuna, sharks, etc.

2. Industrial use: Fish protein is extracted from fish wastes by removing fats. Itis dried and obtained as white powder. It contains 80 to 90% soluble protein.It is used in the preparation of ice cream, paints, varnishes, cosmetics, etc. Fishflour is used in biscuits, bread, cakes and soups, etc. It is easily digestible.

3. Agriculture use: Fish wastes are used as manure for coffee, tea and tobaccocrops. Fish manure (dry powder form) contains nitrogen, phosphorus andcalcium. Dried fish are provided to farm animals, which are good proteinsources.

4. Adhesive: Fish glue is obtained from skin and bones of cod, haddock, pollakand hake. The residue obtained after extraction of glue is used as a poultryfeed and fertiliser after drying.

I Common Edible Fish of India

Fish on the basis of habitat are of three types: Marine or sea fish, brackishwater fish and freshwater fish.

1. Marine fish: These are mackerel, sardines, salmon, bombay duck, etc.

2. Brackish water fish: These are mullet, pearl spot, etc.3. Fresh water fish: These are catla, labeo (rohu), mrigal and reba. Cat fish are

Wallago, Mystus, singhi and magur. All are used as food. Catla is a fast growingfish.

Calla (carp)

Labeo (rohu)

Channel (catfish)

Fig. 3.21 Various Indian freshwater fish

Fisheries

Rearing of fish on commercial scale is called fisheries.Fish are reared in ponds, lakes, rivers, etc. The culture offish is termed as Pisciculture. Fish culture involves collectionof eggs from natural water systems (rivers, lakes), hatchingand nursing in nursery ponds and harvesting.

Han'esting is done when the fish attains themarketable size. During nursing and rearing, fish areprotected from water beetles, bugs and frogs (they cancause harm in fish nurseries), birds and snakes. Fish arealso protected from Infectious Pancreatic Necrosis (lPN)and Viral Haemorrhagic Septicemia (VHS). River andpond water pollution from industrial and urban wastes(sewage) is harmful to fish. The Central Institute ofFreshwater Aquaculture (CIFA), Bhubaneswar, has beendoing enough work on breeding and rearing the catfish(magur). It is an air-breathing fish. Central InlandFisheries Research Institute, Kolkata is also doing work onfisheries.

-----II'fiWilliIDli'l' I."..-J: ----


RMATlVE ASSESSMENTFA 3. :

I -_•1. Growing of wheat and gram on the same field is called _

2. Planting of finger millet (bajra) + cowpea (labia) in alternate rows in the samefield is called _

3. Growing different crops on a piece ofJand in pre-planned succession is knownas _

4. The unwanted plant that grows along with the desired plant is called

5. Diseases in plants are caused by such as bacteria, fungi andVIruses.

6. Fresh initiatives for mcreaSll1g the water available for agriculture include______ and _

FA 3.8: Mapping.tvpe Worksheet

(i) They cuts the root, stem and leaf.(ii) _

(iii) _

Pests attackthe plants in

3 ways

Commonlyknownweeds

are

Pesticides

include

(c;~qo.

~~r:.,(r:vcJ· ,,~~=- L,... u

r; -"~0~-,t"~

Excessiveuse of

chemicalscause

Plant diseases are

caused by pathogens

like

Improvement in Food Resources 123

FA 3.9: Match the FollowingMatch the terms in column I to their meanings in column II.

Column I Column II(a) River Lift Systems (i) Wheat + gram or wheat +

mustard or groundnut +sunflower

(b) Weeds

(c) Inter-cropping

(d) Mixed cropping

FA 3.10: Group Discussion

(ii) Water is directly drawn fromthe rivers for supplementingirrigation in areas close torIvers

(iii) Xanthium, Parthenium andCyperinus rotundus

(iv) Soyabean + maize or fingermillet + cowpea

VK Biology IX 124

Divide the class into small groups. Discuss cropping patterns, irrigation and cropprotection management and discuss the following questions in your group.

I. What is inter-cropping? Give examples.

2. Why should crop rotation be adopted?

3. What is mixed cropping? Give the advantages of mixed cropping system.4. If there is low rainfall in a village throughout the year, what measures will you

suggest to the farmers for better cropping?

FA 3.11: Model Making WorksheetDiscuss with your parents or grandparents about various common agriculturalcrops that used to grow in their nearby farm lands years ago. Carefully note downall the factors that have changed in terms of

• inigation• availability of nutrients-manure and fertilisers

Collect all the information and try to present your information in the form of amodel.

Animal HusbandryThe breeding and rearing of live stock is called animal husbandry. Animal

husbandry is a department under Agriculture which deals with the improvement ofbreeds of canles.

I Breeding of Animals

Animal husbandry department is busy in developing good quality breeds ofcow, buffalo, sheep, goat and fowl, etc., so that farmers get high milk yielding cows,buffaloes, sheep and goats. It improves the economic conditions of farmers.

Breeding is done to produce breeds of cattle with desirable characters.Breeding for increased meat production and breeding for raising good milk yieldingvarieties or dairy breeds. In case of cows and buffaloes, increased milk and butterfat production has been the chief objective of breeding. Many breeds of cattle areavailable for cattle stock improvements. Pure form of a specific breed is cross-bredwith local breeds to obtain cross-breeds to produce increased amount of milk likethe pure breed.


Lactation (milk production) period is an important character among dairybreed cattles. Extended lactation with steady yield per day is a desirable trait. For agood breed, the daily yield will be about 20 to 40 kg of milk with 10 to 11 months oflactation. Dry days, period between lactation and calving during which cows do notmilk, is short. Lactation capacity of a cow depends on the care and nursing duringthe conception period and the after delivery stage.

Cross-breeding is defined as the crossing or mating of animals, belonging totwo different breeds. The offspring thus produced will be of a better quality. Thegovernment has already established more than 150 government cattle breedingfarms for dairy improvement.

Artificial insemination is also a method to inseminate a cow during its heatperiod with stored semen. The semen of the desired bull (ofexotic breed) is collectedin a receptacle and then introduced into the female reproductive tract by manusing instruments. The breeding of dairy cattle by this method has given the dairyindustry the opportunity to make widespread use of superior breeds for improvingthe performance of dairy cattle. Artificial insemination was done for the first timeon dogs by Italian Lazanno Spallarizani in 1780. In India, this was done in 1939 bySampath Kumar in Mysore.

I Advantages of Artificial Insemination

1. It makes selective breeding easier. Semen from any desired bull can be usedto inseminate any cow, selected for breeding. It gives the required type ofoffspring, with a better quality.

2. Attificial insemination is economical. The semen of a bull can fertilise a largenumber of cows.

3. Semen collected from a bull of desired trait can be stored (freezed) for a longtime and can be transported to a long distance wherever needed.

4. Animal breeders can take semen from semen storage banks and thus, there isno need for them to keep a bull for this purpose.

5. Artificial insemination procedure is more reliable. Its success rate is higherthan that of natural breeding.

6. Since semen is easily available whenever needed, a heated female can beimpregnated easily.

Milk is a very important supplementary diet of man. In India, milk is theonly source of animal protein food for the vegetarians. In the infant stages of man,milk is the sale dietary food. Cows and buffaloes are the primary producers of milk,although goat and sheep also yield milk.

Embryo transfer

This technique is used for improving the animal breed. The developingembryo at a definite stage is taken out from the uterus of a superior breed andtransferred into the uterus of a female of inferior breed. Here, it develops till birth.Thus, the quality and production in livestock can be improved.

Feeding and Shelter of Milk Animals

For getting good, clean and proper yield of milk, the animals need dailyregular brushing and bathing. Their shelters should be roofed to protect them fromun's heat, rain and cold. The floor of the shed should be on a slope so that it is easily

cleaned and it should also be dry. They should be spacious enough. A cow generallyneeds about six square metre space and a buffalo needs a little more space. The

mprovement in Food Resources 125 VK BIOlogy IX --'.' ,

cattle shelters should also be well ventilated. For their feeding there should be longfeeding troughs and feeding passages.

I Food

Cattles (cows and buffaloes) suffer from various diseases. which cause reductionor stoppage of milk production. Certain diseases even cause death of the cattle. Ahealthy animal shows regular normal feeding. normal body posture. normal bodytemperature (38°C in cow) and pulse rate from 40 to 60 per minute. The normalrespiratory rate is 15 to 30 per minute in cows. In buffalo, the body temperatureis 37.2 to 38.2°C. pulse rate is 40 to 45 per minute. and respiration rate is 16 to 18per minute.

Diseases of cattles are of three types:

(I) Parasitic (2) Infectious and (3) Non-infectious.

1. Parasitic diseases: Fleas. blood sucking lice. ticks and mites are externalparasites. They live on the skin of cattles and cause skin diseases. Cattle leech(Hirudinaria granulosa) sucks blood of cattles (cows and buffaloes) and causeanaemia. Internal parasites of cattles are Ascaris sps. (worms) living in intestine,causing anaemia and intestinal disorders. and Fasciola sps. (flukes) damage theliver.

2. Infectious diseases: They are caused by bacteria and viruses. They arecontagious and spread by contact from animal to animal. Bacterial diseases


Diseases of Cattles

The animal food includes roughage and concentrates.

1. Roughage largely contains fibres like green fodder. silage. hay of cereals andlegumes such as barseem, lucerne, cowpea and agath.

Green grasses are the most common nutritious food of cattles. These areSudan grass. Rhodes grass, Napier grass. Guinea grass and Elephant grass,etc. Barseem, lucerne. cowpea and agathi are the leguminous fodder relishedby cattles very much. Barseem and lucerne are available in winters as well as insummers. Jowar is also a green fodder of summers. Maize and bajra are usedas dry fodder in summers. In winters, green upper part of sugarcane is alsogiven to the cattles. which is also a nutritious food for animals.

2. Concentrates are low in fibres and contain relatively high proteins and othernutrients. Concentrates are rich in carbohydrates. fats, proteins, vitamins andminerals. Concentrate foods are cotton seeds, oil seeds. grains of maize, barley,oats.jowar. bajra. gram and their byproducts. e.g.• rice and wheat barns, gramhusk. oil seed cakes. etc. Oil seed cakes (khal) in water is mixed with the hay ofcereals to produce the nutritious nature of food. Cotton seeds are given to thecattles to increase fat content of the milk.

The daily (24 hours) balanced ration (feed) of a cow is as follows:

I. Green fodder (roughage) = 15 to 20 kg.

2. Concentrate (grain mixture) = 4 to 5 kg.

3. Water = 30 to 35 litres.

Thus. milk-yielding cattles need a good nutritious feed daily for the productionof fairly good milk. Additional vitamins, hormones and minerals may also be givento cattles for their good health, and good yield of milk. Antibiotics may also be givento them to protect them from diseases.

126iiidI'---!.:.~;

are anthrax, black quarter, (from Clostridium chanroei) and haemorrhagicsepticemia caused by Pasteurella multocida.

Viral diseases are cow pox (Vaccinea), rinder pest and foot and mouth disease.In foot and mouth disease, blisters appear in mouth and on feet. Saliva oozes out ofmouth in excess, there is soreness of mouth, appetite diminishes and there is highfever. It even causes death to cattles.

There are certain bacterial, viral and fungal diseases of animals that aretransmitted to human beings. So one should be careful to prevent and control suchdiseases. These are rabies, cow pox, encephalitis (viral), anthrax, tuberculosis andbrucellosis (bacterial) and actinomycosis, aspergilosis and ring worm (fungal). Certainprotozoan parasites (e.g., Entamoeba and Trypanos01l!a) also cause infection in man.For bacterial and viral diseases, vaccines have been developed and are available inthe market. For controlling various types of diseases in cattles and domestic animals,veterinary hospitals are present in every district and town of the country.

I Prevention of Animal Diseases

I. Animal shelters should be well-cleaned and aerated.

2. Animals should get good food and clean drinking water.

3. Their regular bathing is also essential for preventing external parasites. Ifexternal parasites infest the animal, apply solution of insecticides.

4. Diseased animals should be kept separate.

5. Vaccination may be done against bacterial and viral diseases.

6. Prevent rats from entering animal shelters.

I Meat Providing Livestocks

Goat, sheep and pig together supply about seventy per cent meat in India.Goat meat demand is more than sheep and pig meat. Sheep and goat also providemilk and wool. Their maintenance is also easy. Sheep do not need a good shelter.They can live in flocks under natural shades of trees and hills. Sheep eat a variety ofplants including weeds. Indigenous breeds of sheep are Nellore and Mandya, andDorset and Suffolk are exotic breeds. Indigenous breeds are famous for productionof wool and exotic breeds for mutton. Their cross breeds gain 30 to 50 per centmore body weight. Hence, they are better for the production of mutton.

Indigenous breeds of goat in our country are about twenty. These areJamunapari, Himalayan, Bengal and Assam hill breed, Decanny and Osmanabadi,Kathiyabari, etc. Popular exotic breeds are Alpine, Toggenberg and Sannen. Goats'shelter should be dry, safe and secure from predators (e.g., wolves) and protectedfrom too much heat and cold. Goats need fresh and clean fodder, hay ofleguminouscrops and leaves of trees. A goat requires about 5 kg roughages (green and dry) and250 g concentrates.

Common diseases ofsheep and goat are caused by bacteria and virus. Bacterialdiseases are Black quarter, Brucellosis and Vibriosis. Sore mouth, goat pox andrinderpest are viral diseases. Nutritional deficiency disease also occur in goats. Theyalso suffer from parasitic attack. Regular vaccination, cleaning and consultation withveterinary doctors are essential to prevent diseases.


Table 3.15 Diseases of animals


Bee KeepingNector, a sweet viscous liquid secreted by flowers is suck by bees and converted

to honey by the action of an enzyme-invertase. It is then stored in special cells ofhives. This honey is ofenormous use to man. It is a sweet viscous fluid, rich in sugars,minerals, vitamins, amino acids and enzymes. Honey has great nutritive value andmedicinal value. It is an essential requirement for children as it is rich in iron andcalcium and helps the body to grow. Honey is a source of sugar in confectioneryitems like pastries and cakes. Its medicinal uses are wide. It is a blood purifier andcures cough and cold. It also cures ulcers of throat, tongue, stomach and intestine.In addition, beehives are also a source of wax, propolis and bee venom. Wax issecreted by wax glands of worker bees and is utilised in the construction of hives.This wax is ofgreat use to us. It is used in the manufacture ofcosmetics, cold creams,shaving creams, lipsticks, nail polishes, candles, ointments, lubricants, etc.

Propolis are another collection of bees from the plants used in repairing andfastening combs. Bee venom is used in the manufacture of certain Ayurvedic andHomeopathic medicines. Keeping all this in mind, bee keeping for obtaining honeyand other useful materials has become an agricultural enterprise. The practice ofbee keeping is called apiculture.

I Honey Bee Varieties Used for Bee KeepingBoth indigenous and exotic varieties of honey bees are used for commercial

production of honey in India.1. Indegenous Varieties of Honey Bees include, Apis cerana indica F. (Indian

bee). Apis dorsata F. (Rock bee), Apis florae F. (Little bee).2. Exotic Varieties of Honey Bees are Apis mellifera (European or Italian bee),

Apis adamsoni (South African bee).The South African bee yields 100 kg per hive per year which is twelve times

the Indian average of 4.5 kg per hive per year. The Italian bee yields an averageof 50 to 200 kg of honey per hive per year. Italian bee (APis melli/era) is commonlydomesticated in India to increase the yield of honey.

I Colony of BeesHoney bee is a social insect that lives in colonies and provides a very good

example of division of labour and caste system. Different tasks are done by differentgroups ofbees in the same colony. A colony may have 40,000 to 1,00,000 individuals.Individuals show polymorphism, i.e., individuals show a distinct form of variation inmorphology. There are three castes-queen, drones and workers-individuals of eachcaste are morphologically distinct from those of others.

Queen

It is generally one in a colony and is the largest. The queen remains inside thehive and lays eggs. It lays up to 2,000 eggs everyday, both fertilised and unfertilised.I t is fed on proteinaceous food like royal jelly.

I Animal diseasesAnimal I I , .-

Bacterial Viral Fungal

Cattles (cow. buffalo, sheep) ITuberculosis IFoot and mouth -

Cattles (cow, buffalo, sheep) Rinderpest Pox -

Cattles (cow, buffu.lo, sheep) ISalmonellosisIRanikhe~

-

Poultry birds Fowl pox I Aspergillosis

128

Fig. 3.22 Honey bee

VK Biology IX.;'--

Drones

They emerge from the unfertilised eggs and are fertile males. They arestingless and medium sized. Their role is to mate with the queen, eat honey andremain inside the hives. They are driven away from the hives to save the honey.

Workers

They emerge from the fertilised eggs and are sterile females. They are thesmallest in size but are the most active of all. They have pollen sacs, sting and waxglands and perform all domestic and field works. During the initial period of theirlife, they perform indoor duties like cleaning up the cells before the queen bee layseggs in them. Then they build new combs and seal them with wax. In the later stageof life they do the outdoor activities like collection of nectars from flowers and storethem in storage cells and convert them into honey by their enzyme actions. Theyalso defend their colony from enemy by stinging it. They immediately die off afterstinging.

Apiculture and management of honey production is a fast growing cottageindustry in India with about 5.75 lakh bee colonies working to produce honey atpresent. According to rough estimates, the total output of honey in India at presentis about 5 million tonnes per annum. Tamil Nadu is the top honey producer{o"",""d b~ K,,-,a\a a"d Kan,atal,;.a. fm I:0mm,,-,c,a\ pYDduct\Dn Df 'uDnq, ap\a,\e:.are established. An apiary is a place where bee hives are kept to obtain honey andother bee products.

Beehive

A beehive is a special box of wooden chambers forlaying eggs and honey collection. There are three types ofartificial beehives used in India:

• Langstroth • Newton • Jeolikote

While the Langstroth beehive is used in hilly regionsthe latter two are formed in plains.

The quality and taste of honey depends upon theflora or orchards available in the near vicinity of theapiary. Apiaries are situated near mango groves, coconuttrees, almond trees, apple trees, orchards of cashew nuts,guava trees and honey obtained from these apiaries taste Fig. 323 BeehIVe

accordingly. Almond honey of Kashmir tastes very good.

A suitable site of apiary should have abundance of flowers with a longer honeyflow time (the total time during which bees collect nectar and pollens).

It should receive sunlight during morning and evening and some shadeduring mid-day.

Water should be available nearby.

I Selection of Honey Bee Variety

The Italian bee, Apis melliferia, is most widely used for honey production inIndia. This bee yields an average of 50 to 20 kg of honey per hive per year.

I Diseases and Enemies of Honey Bee

Honey bees are commonly infected by viruses, bacteria, fungi and protozoa. Forexample, the bacterium Bacillus apisceptio!ls infects blood of bee causing septicemia.Brood foul disease is caused by Schizomycetes (fungi). Nosema disease and

Improvement in Food Resources 129,.'

oysters

amoeba diseases are caused by protozoan pathogens Nosema apis and Vahlkampflamellifira, respectively. Common pests/enemies of bees are wasps, wax moths andmites. Various birds such as king crows, blue tits, fly-catchers, chaffinch, green blueeater, sparrows, etc., use bee as their meal. Wasps are controlled manually (i.e., bydestroying the wasp nests from the locality of apiary). Wax moth is controlled byexposing bees in bee hive to sun, by increasing temperature. Bee-eating birds arescared away by some device.

FORMATIVE ASSESSMENTFA 3.12: Word Box

Topic: Fish production

Directions: Complete the paragraph given below choosing the appropriate wordsfrom the word box in the space provided.

catlas pomphret, mackerel and Bombay duck

mullets bhetki and pearl spots rice crop

Mrigals and Common Carps composite fish culture system

Grass Carps five or six

The water source of the fish can be either sea water or fresh water, such as in

rivers and ponds. Popular marine fish varieties include _

_________and , . Marine

fish are caught using many kinds of fishing nets [Tom fishing boats. Some

marine fish of high economic value are also farmed which include finned fish

like , and

_________are also cultivated for the pearls they make. Fresh

water resources include canals, ponds, reservoirs and rivers. Fish culture is

sometimes done in combination with a ,--------,so that fish are grown in the water in the paddy field. More intensive fish

farming is done in . In such a system, a combination of

_________ or fish species is used in a single

fishpond. As a result, the food available in all the parts of the pond is used.

As are surface feeders, feed in

the middle-zone, and are bottom

feeders, and feed on the weeds.



r. Jersey is an Indian breed of cow.

2. To enhance poultry production, cross breeding is done between Indian andexotic breeds for variety improvement.

3. To increase the production of fish, they can be cultured in marine and inlandecosystems.

4. Poultry farming is done to raise domestic fowls for egg production and chickenmeat.

5. Most fish production in inland waterbody is capture fishing.

.. 130 Improvement in Food Resources

6. One major problem with composite fish culture is that many of these fish breedonly during monsoon.

7. The value or quality of honey depends upon the pasturage, or the flowersavailable to the bees for nectar and pollen collection.

A dorsata,

(vi) Aseel

(vii) Pearls(viii) Draught animals

(ix) Middle-zone feeders

(x) Culture fishery(xi) Apis cerana indica,

A florae

FA 3.14: Match the Following:Match the terms in column I to their meanings in column II.

Column I Column II

(a) Catlas (i) Broiler

(b) Rohus (ii) Surface feeders(c) MrigaJ (iii) Bottom feeders

(d) Fish farming (iv) Milk-producing females

(e) Bees used for commercial (v) Local breed of cattlehoney production

if) Oysters

(g) Cattle used for tilling and carting

(h) Indian breed of chicken

(i) Sahiwal and Red Sindhi(J) Milch

(k) Chicken better food for obtaining meat

FA 3.15: Bead Necklaces

Given below are outline structures ofsome 'Bead Necklaces' and a list ofcharactersplaced in different categories. Each necklace is given a name that is actually the'term' important for Food Production. You have to pick one character from eachcategory to list the features of a group. In this way, you will 'string the beads' andthe necklace will be complete when all the beads have been allotted charactersfrom each category.

Categories A B C D E•For Milk Layers and Fowl Dwarf parent Mullets and

and broilers preferred for BhetkiDraught commercial chicklabour production

For egg Marine and Peneaus Lactation period Aseelandproduction fresh water monodon is important while Leghornand chicken varieties selecting the right

meat breed

Cheap Dairy and Apis Large schools are Jersey, Redsource of draught dorsO-la~ located in open Sindhi

animal animals Apis sea using satellitesprotein melliJera and eeo-sounders;

obtained Capture andfrom water culture methods

are also used

For Local and Bas indicus Value or quality of Rock beeproduction Italian and Bos product depends and little bee

honey variety bubalis upan pasturage

Improvement in Food Resources 13l VK Biology IX ---"

A

B

~FARMING

co

E

E

E


o

oc

.~FARMING

c

~PRODUCTION

B

A

132

---:,.VK Biology IX133

E

oc

rBEE"\KEEPING

B

A

SUMMARY

FA 3.16: Group Discussion

Divide the class in small groups. Discuss animal husbandry and discuss followingquestions in your group.

I. Name the method commonly used for improving cattle breeds and also statewhy it is used.

2. Name any two Indian breeds of (i) cows and (ii) buffaloes.3. Define animal husbandry.4. How is cross breeding useful in cattle?

I Human beings use plants and animals as food.

I Plants are autotrophs, i.e., they manufacture their food as starch (carbohydrate).

I Animals and human beings are heterotrophs, i.e., feed on plants and animals.I Plants get carbon and oxygen from air, hydrogen from water and rest from the soil to

manufacture food through a process called photosynthesis.I Man is constantly trying to improve the quality and increase the quantity of food to

support a growing population.

I Improvement in yield of crops should be done in three stages:-crop variety improved-crop production management-crop protection management

I While the first stage includes selection of an improved variety of seeds throughhybridisation and genetic engineer, the second stage deals with nurturing of cropsthrough nutrient management, cropping pattern, irrigation, etc. The third stage isprotection of the harvest.

I Manures are natural bulky organic matter, e.g., farmyard manure (FYM), compost,green manure and vermicompost.

I Manures restore the soil texture for water retention and soil aeration.

I Manures provide food for soil organisms, like bacteria and fungi. They decomposeorganic matter and provide nutrients to plants.


I FYM is a decomposed mixture of cattle's excreta, roughage or unused fodder. Itprovides nitrogen, phosphorus and potassium to the crop.

I Compost is vegetable and animal refuse of town area, like animal excreta, faecalmatter of humans and sewage waste. It is decomposed by microorganisms. It containsthe same nutrients as that of FYM.

I Green manuring is growing of leguminous and non-leguminous crops in the field,ploughing (before flowering) and mixing with the soil.

I These are decomposed in the soil by microorganisms. This is done before rains.Leguminous plants provide nitrogen to the soil.

I Fertilisers are chemicals produced by the factories. These are inorganic, e.g.,ammonium sulphate and organic like urea. Fertilisers are nitrogenous (urea,ammonium sulphate, sodium and ammonium nitrate), phosphatic (superphosphatesand dicalcium phosphate), potassic (potassium chloride, sulphate and nitrate) andcomplex like nitrophosphate, ammonium phosphate, urea ammonium phosphateproviding two or more nutrients.

I Biofertilisers add nitrogen to the soil. These are cyanobacteria, phosphate solubilisingmicroorganisms, Rhizobium, blue-green algae, and mycorrhiza (fungi lives in roots ofhigher plants).

I Water is very essential for crop production. Its judicious use increases the crop yield.Where water is not available for irrigation, crop yield is low. Crop production entirelydepends on rain water.

I Insufficient rain or no rain creates drought condition. Crops dry off.

I Crop protection is to protect the crop from pests, i.e., insects, fungi, bacteria,viruses, worms, rodents, etc. Insects are killed by insecticides, fungi are destroyed byfungicides. Chemicals used to kill pests (e.g., weeds, fungi, insects, mites and rodents)are called pesticides. Pesticides are either sprayed or dusted over crops, or mixedwith seeds and soil.

I For preventive measures for the crops- resistant varieties of crop plants, crop rotationand multiple cropping and summer ploughing are used.

I Contact insecticides are malathion, lindane and thiodon. They are sprayed on stemand leaf cutting and boring insects.

I Systemic insecticides are dimethoate and metasystox. These are also sprayed. Theseare absorbed by the plants. When sap sucking insects feed on plants they are killed.

I Sucking insecticides are aphids (Aphis), Pyrilla (leaf hoppers), plant bugs like redcotton bug (Dysdercus ).

I Plant borers are sugarcane borers, chick pea pod borers, cotton boll weevil and grainweevil.

I Weeds are small sized unwanted plants growing along with cultivated crops in thefield. They suppress the growth of the crop plants and use nutrients from the soil.Examples of weeds are motha (nut grass), jangJi jowar (wild sorghum), chau/ai,sathi, jangJi jar, bathua and hirankhuri. Chemicals used for destroying weeds are 2,

4-dichlorophenoxy acetic acid, atrazine, f1uchoralin, etc. Biological control is done bycochineal insects for Opuntia; grass carp (fish) is used to control aquatic weeds.

I Pests of stored grains are pulse beetle damage grams; rice weevil damage rice; wheatweevil, grain and flour moth of rice, wheat, maize, etc., rust red flour beetle, rice moth andlesser grain borer. Their adults or larva (grub) or both damage the grains and their flour.

I Grains (rice, wheat, etc.) are stored in gunny bags and FCI silos.

I For storage of grains, temperature of storage houses should not be more than30·C and moisture content should be 14% or less by weight. More humidity causesdevelopment of fungus.


• Storage places should be cleaned, free from cracks or holes in the walls, etc., gunnybags should be stitched properly after filling grains and if needed the place should befummigated.

• Spray insecticides over grain-filled gunny bags. Gammaxene or benzene hexachloridewettable powder (BHC WP), pyrethrum and malathion are some insecticides to name.

• Fumigants are ethylene dibromide (EDB), ethylene dichloride plus carbon tetrachloride(EDCT) in liquid form; aluminium phosphide (AlP) in solid state and methyl bromide ingaseous state.

• Animal husbandry deals with the breeding, feeding, rearing, shelter and caring ofdomestic animals and meat and egg giving animals, etc.

• Objective of animal husbandry is to improve cattle and live stock breeds to get higheryields of milk, meat, eggs, wool, etc.

• Improved Indian breeds of cows are Red Sindhi and Tharparkar of Andhra Pradesh, Girof Gujarat, Sahiwal of Punjab and Haryana.

• Exotic breeds of cows are imported breeds brought from European countries. Theseare high milk yielding cows, e.g., Holstein, Swiss, Jersey and Friesian.

• Improved cow-breeds developed by NDRI, Kamal are Karan Swiss (Swiss X Sahiwal),Karan Friesian (Tharparkar X Holstein Friesian) and Frieswall (Sahiwal X HolsteinFriesian).

• Buffalo breeds are Murrah of Punjab and Haryana, Mehsana and Surti of Gujarat.

• Sheep are reared for milk, meat, wool and hide. Their important breeds are Gaddi andRampuri of Himalayan region, Bikaneri, Marwari and Deccani.

• Important breeds of goats are Kashmiri, Gaddi and Surti

• Poultry breeds are White Leghorn, Minorcha and Rhode Island Red. They lay about200 to 300 eggs per year.

• Desi or indigenous breeds are Brahma, Chittagong, Aseel and Basara, etc., which layonly 60 to 75 eggs per year. Their eggs are smaller in size. But these are good sitters.

• Improved poultry cross breeds are B-n, HH266 and ILS-80.

• Fish farming is called pisciculture. Fish is a good source of meat. Fish liver oil is rich invitamin A and D and is an unsaturated oil.

• Marine fishes are salmon, sharks, etc.

• Fresh water fishes are rohu, catla, mrigal. These are called major carps. Other fish areWallago (malli), Mystus (singhara), C1arias (mangur) and singhi.

• Artificial fish breeding is done in Indian Veterinary Research Institute, Izatnagar,Bareilly.

• Fresh water fish are cultured in hatcheries, bunds, rivers and ponds, etc.

• Breeding of animals (cows and buffaloes) is also done by artificial means, i.e., byartificial insemination. It is the introduction of semen of good variety bull into thefemale reproductive tract by the means of a special instrument.

• Artificial Insemination is better than Natural Mating.

• Operation flood (white revolution) is to increase milk yield of milch animals. Dr. Kurienis the father of white revolution. He is an architect of India's modern dairy industry.

• NDDB is National Dairy Development Board.

• VHS is viral haemorrhagic septicemia, a disease of fish.

• IPN is infectious pancreatic necrosis, a disease of fish.

• NDRI is National Dairy Research Institute, Kamal.

• Pasteurisation is a process to kill microorganisms of milk which cause spoilage. Milk isheated at a high temperature and then brought down to room temperature.


FA 5. Multiple Choice Questions

Select the right choice.1. Find out the wrong statement from the following

(a) White revolution is meant for increase in milk production.(b) Blue revolution is meant for increase in fish production(c) Increasing food production without compromising with environmental quality is called

as sustainable agriculture.(d) None of the above

2. To solve the food problem of the country which among the following is necessary?(a) Increased production and storage offood grains(b) Easy access of people to the food grain(c) People should have money to purchase the grains(d) All of the above

3. Find out the correct sentences(i) H ybridisation means crossing between genetically dissimilar plants

(ii) Cross between two varieties is called as inter specific hybridization(iii) Introducing genes of desired character into a plant gives genetically modified crop(iv) Cross between plants of two species is called as inter varietal hybridization

(a) (i) and (ii) (b) (ii) and (iv)

(c) (ii) and (iii) (d) (iii) and (iv)

4. Find out the correct sentence about manure(i) Manure contains large quantities of organic matter and small quantities of nutrients.

(ii) I t increases the water holding capacity of sandy soil.(iii) It helps in draining out of excess of water from clayey soil.(iv) It excessive use pollutes environment because it is made of animal excretory waste.

(a) (i) and (iii) (b) (i) and (ii)


5. Cattle husbandry is done for the following purposes(i) Milk production (ii) Agricultural work

(iii) Meat production (iv) Egg production(a) (i), (ii) and (iii) (b) (ii), (iii) and (iv)

(c) (iii) and (iv) (d) (i) and (iv)

6. Which of the following are Indian cattle?(i) Bos indicus (ii) Bos domestica

(iii) Bos bubalis (iv) Bos vulgaris(a) (i) and (iii) (b) (i) and (ii)


7. Which of the following are exotic breeds?(i) Brawn (ii) Jersey

(iii) Brown Swiss (iv) Jersey Swiss(a) (i) and (iii) (b) (ii) and (iii)

(c) (i) and (iv) (d) (ii) and (iv)

8. Poultry farming is undertaken to raise following(i) Egg production (ii) Feather production

(iii) Chicken meat (iv) Milk production(a) (i) and (iii) (b) (i) and (ii)


miii'iJiiil138 Improvement in Food Resources

9. Poultry fowl are susceptible to the following pathogens(a) Viruses (b) Bacteria(c) Fungi (d) All of the above

10. Which one of the following fishes is a surface feeder?(a) Rohus (b) Mrigals(c) Common carps (d) Cadas

11. Animal husbandry is the scientific management of(i) animal breeding (ii) culture of animals

(iii) animal livestock (iv) rearing of animals(a) (i), (ii) and (iii) (b) (ii), (iii) and (iv)

(c) (i), (ii) and (iv) (d) (i), (iii) and (iv)

12. Which one of the following nutrients is not available in fertilizers?(a) Nitrogen (b) Phosphorus(c) Iron (d) Potassium

13. Preventive and control measures adopted for the storage of grains include(a) strict cleaning (b) proper disjoining(c) fumigation (d) all ofthe above

Answers

FA 6. Flow-chart Worksheet

::ailed

1. (d)

9. (d)

2. (d)

10. (d)

3. (a)

11. (d)

4. (b)

12. (c)

5. (a)

13. (d)

6. (a) 7. (b) 8. (a)

Instructions: Identify the missing steps/processes/examples in the flowchart given below andcomplete it using the appropriate words.

• • •

Crop VarietyImprovement

Improvement in

Crop __---,Improvement

Crop ProtectionManagement

Yield

ImprovedQuality

and AbioticRessistanc

Change in

WiderAdaptability

Desirable

NutrientManagement

andMacronutrients

Manures and

IrrigationWells,

Canals,River liftsystems

andtanks

MixedCropping

Protection inthe field against

Weeds,Insects and

Pests

Protectionduring

Storage againstBiotic and

Abiotic Factors

Methods of CropVariety Improvement1. Hybridisation2. Genetic manipulation (GMO)


CropRotation

139

FA 7. Worksheet

Instructions:

• Given below are five pictures related to Food Production.

• Provide a title for these pictures from the terms given here, in the space provided.

Mariculture Multiple Cropping Composite Fish Culture Poultry Livestock Farming

• State one desirable characteristic or advantage of each of these.

• These may be written on a separate sheet.

f'

(Rearing varieties of Hen)

t

4. _

~

.;

- ~.N

~~~~~~~~~.

~~U®H~II"\.y'II "

ttttt ' .'~:"

5. _

~~

~,- --"C-

(Growing Catla, Rohu, Grasscarp andmrigal together)

~(Growing Peneous monodonThe prawn found in sea)

3. _1. _

(Growing crops on thesame land)

FA 8. Paper Pen Test

1. Answer the following question.(a) What is GM crop? Name anyone crop which is grown in India.

(b) Why is organic matter important for crop production?(e) Define the terms hybridisation and photoperiod.

(d) Cultivation practices and crop yield are related to environmental conditions. Explain.

(e) Discuss the role of hybridisation in crop improvement.

If) Why bee keeping should be done in good pasturage)

2. Fill in the blanks.(a) Kharif crops are cultivated from to _

(b) Rabi crops are cultivated from to _

(e) Most of the food comes from and animal husbandry.

~.~140 Improvement in Food Resources

(d) Milk production can be increased by increasing period.(e) Pigeon pea is a good source of _

3. True or False.(a) Mullets are marine fish farmed in sea water.

(b) Poultry production involved egg production and broiler production for poultry meat.

(c) The growing of different crops on a piece of land in pre-planned succession is calledinter-cropping.

(d) Organic farming is a fanning system with maximum or excessive use of chemicals asfertilisers, herbicides, pesticides, etc. and with minimum input of organic manures andrecycled farm wastes.

4. Match the following.

Column I Column II

(a) The value or quality of honey depends (i) Many of the fishes breed only duringupon monsoon.

(b) Problem with composite fish culture (ii) Pasturage or the flowers available to thebees for nectar and pollen collection.

(c) Broiler chicken are fed vitamin like (iii) Milk and draught labour.

(d) Cattle husbandry is done for two purposes (iv) Vitamins A and K.

(e) Food stuff provide proteins (v) Soyabean, ground nut, seasame, castor,mustard, linsead and sunflower.

if) Food stuff provide fats (vi) Gram, pea, black gram, green gram,pigeon pea, and lentil.

5. Multiple Choice Questions

(a) Which one is an oil yielding plant among the following?(i) Lentil (ii) Sunflower

(iii) Cauliflower (iv) Hibiscus

(b) Weeds affect the crop plants by

(i) killing of plants in field before they grow.(ii) dominating the plants to grow.

(iii) competing for various resources ofcrops (plants) causing low availability of nutrients.

(iv) all of these.

(c) Which of the following is an Italian bee variety?

(i) Apis Cerana indica (ii) Apis mellifera

(iii) Apis dorsata (iv) Apis florae(d) Which of the following combinations are most suitable for composite fish culture?

(i) Surface feeders and bottom feeders(ii) Surface feeders, middle zone feeders and bottom feeders

(iii) Middle zone feeders and bottom feeders

(iv) Surface feeders only

(e) Which of the following is not a source of carbohydrate?

(i) Rice (ii) Millets(iii) Sorghum (iv) Gram


SUMMATlVE ASSESSMENTA. Textbook Questions with their Answers

1. What do we get from cereals, pulses, fruits and vegetables?

Ans. Cereals like wheat and rice provide us carbohydrates for fulfilling the body's energyrequirement. Pulses like gram and peas provide us with proteins. Fruits and vegetablesprovide us with a range of vitamins and minerals in addition to some proteins, carbohydratesand fats.

2. How do biotic and abiotic factors affect crop production?Ans. Biotic factors like diseases, insects and nematodes, and abiotic factors like drought, salinity,

waterlogging, heat, cold and frost have a negative impact on crop production, i.e., the cropyield decreases due to these factors.

3. What are the desirable agronomic characteristics for crop improvements?

Ans. For fodder crops, height and profuse branching are desirable characteristics. For cereal crops,dwarfness is desired, so that less nutrients are consumed by the crops. In this way, developingvarieties of desired agronomic characters give higher productivity, i.e., higher yield.

4. What are macronutrients and why are they so called?

Ans. Sixteen nutrients are essential for plants, out of which thirteen are supplied by the soil. Amongthese, six are required in large quantities. As these are required in large quantities, they are calledmacronutrients. They are: (1) niu'ogen (2) phosphorus (3) potassium (4) calcium (5) magnesiumand (6) sulphur.

5. Where do plants get nutrients from?

Ans. Plants get nutrients from air, water and soil. There are basically sixteen nutrients that areessential for plants. Of these, carbon dioxide and oxygen are obtained from air, hydrogenfrom water and the rest of the thirteen nutrients are supplied by the soil.

6. Compare the use of manures and fertilisers in maintaining soil fertility.

Ans. Manures are rich in organic matter but are poor in nutrients. For this reason, the cultivatedfield supplied with only manures may suffer from deficiency of nutrients which willautomatically result in poor yield; whereas fertilisers are inorganic compounds and fulfilnutrient requirement of soil. So, the field which is supplied with fertilisers only may facedrainage problem and waterlogging due to lack of organic matter in the soil which will bringharm to the crop and the yield. Moreover, the use offertilisers over long periods of time candestroy the soil structure by killing the soil microorganisms that recycle nutrients in the soil.

7. Which of the following conditions will give the most benefits? Why?(a) Farmers use high-quality seeds, do not adopt irrigation or use fertilisers.(b) Farmers use ordinary seeds, adopt irrigation and use fertilisers.

(e) Farmers use quality seeds, adopt irrigation and use fertilisers and crop protection measures.

Ans. Conditions given in (e) will give the most benefits because:

(a) Farmer will benefit by using quality seeds.

(b) Proper irrigation will overcome drought or flood situations.(e) Fertilisers will provide nutrients and there will be higher yield.

For most benefits, every aspect of agriculture should be taken care of.

8. Why should preventive measures and biological control methods be preferred for protectingcrops?

Ans. Preventive measures and biological control methods are preferred because:

(a) They are simple.

(b) They are more economic.(e) They minimise pollution without affecting the soil quality.


9. What factors may be responsible for losses of grains during storage?Ans. The following factors are responsible:

(a) Abiotic factors like inappropriate moisture and temperature.(b) Biotic factors like insects, rodents, birds, mites and microorganisms.

10. Which method is commonly used for improving cattle breed and why?

Ans. The commonly used method for improving cattle breed is cross-breeding two cattles havingthe desired qualilties.For e.g., by crossing Brown Swiss having long lactation periods is crossed with Red Sindhihaving disease resistance to get a breed having both qualities.

11. Discuss the implications of the following statement: "It is interesting to note that poultryis India's most efficient converter of low fibre food stuff (which is unfit for humanconsumption) into highly nutritious animal protein food."

Ans. The feed consumed by poultry birds is fibrous and cheap. Moreover, it is formulated usingagricultural by-product. In this way, the product not used by human population are convertedinto chicken meat and the eggs produced by poultry birds, which are highly nutritious andare used by humans.

12. What management practices are common in dairy and poultry farming?Ans. (a) Shelter: In both dairy and poultry farming, should be, well-designed, airy and hygienic

shelter.(b) Feeding: Healthy feed is provided to both dairy animals and poultry birds to get good yield.

(c) Caring for animal health: Both animals and birds must be protected from various diseases.

13. What are the differences between broilers and layers and in their management?

Ans. The broiler is a poultry bird specially groomed for obtaining meat and layer is the egglaying poultry bird. As per the purpose for which they are raised the housing, nutritional andenvironmental requirements of broilers are somewhat different from those of the layers. Thedaily food requirement ration for broilers is protein-rich with adequate fat and high amountof vitamin A and K; whereas the layers require enough space and proper lighting.

14. How are fish obtained?

Ans. Fish are obtained by either from the natural resources which is called capture fishing or byfish farming which is called culture fishery.

15. What are the advantages of composite fish culture?

Ans. The advantages of composite fish culture are:(a) The species are selected in such a way that they do not compete for food among themselves,

and have different types of food habits. Due to this, the food available in all parts of thepond is used. For example, Catlas are surface feeders, Rohu feed in the middle-zone ofthe pond, while Mrigals and common carps are bottom feeders. Also, Grass Carps feed onthe weeds.

(b) All these species together use all the food in the pond without competing with each other.(c) This increases the fish yield from the pond.

16. What are the desirable characteristics of a bee for honey production?

Ans. Desirable characteristics of a bee for bee-keeping are:

(a) Good honey collection capacity.(b) Ability to protect itself from enemies.(c) Prolific queen production with less swarming.

17. What is pasturage and how is it related to honey production?

Ans. The flora/crops found around an apiary to collect honey and pollen grains is called pasturage.Pasturage flora of honey bee includes Mango, Coconut, Almond, Apple, Tamarind, Sisam,Mahua, etc.


The quality and taste of honey depends upon the flora/pasturage around the apiary fromwhich bees collect the nectar and pollens. For instance, the Kashmir region having almondplant pasturage around apiary produces almond honey which is good in quality, taste as wellas aroma.

18. Explain anyone method of crop production which ensures high yield.Ans. Use of manures and fertilisers ensure high yield. Manures are important source of nutrients

whereas fertilisers provide nitrogen, phosphorus and potassium to the crops. For the propergrowth of crops and for high yield, all the nutrients, both macronutrients and micronutrientsmust be provided to the crops. Manures add humus to the soil which makes the soil veryfertile.

19. Why are manures and fertilisers used in the fields?Ans. Manures and fertilisers are used in the fields to make the soil fertile by improving the soil

texture and nutrient content of the soil.

20. What are the advantages of intercropping and crop rotation?

Ans. Advantages of intercropping:(a) In intercropping, two or more crops are simultaneously grown on the same field in a

definite row pattern-a few rows of one crop and adjoining to that a few rows of anothercrop. This practice reduces intraspecific competition.

(b) This ensures that both crops can give better yield.

(e) There is maximum utilisation of nutrients and minimum spread of pests.

Advantages of crop rotation:(a) It makes the soil fertile and helps in the increase of crop yield.

(b) It also decreases the demand of nitrogenous fertilisers as leguminous plants grown duringcrop rotation fix the atmospheric nitrogen.

(e) The selected rotation ofcrops also helps in pest control, as pests do not find their favouritecrop in the next season and it becomes difficult for them to survive there.

21. What is genetic manipUlation? How is it useful in agricultural practices?

Ans. Incorporating desirable characters by hybridisation, mutation, DNA recombination, etc., iscalled genetic manipulation. By genetic manipulation, we get improved varieties of seedshaving desired characters like pest and disease resistance and high yield. Their seeds not onlygive higher yield but also reduce the input cost.

22. How do stored grain losses occur?

Ans. There are two types of factors responsible for losses during storage of grains. These are:(a) Biotic factors such as insects, rodents, mites and bacteria.

(b) Abiotic factors such as temperature, moisture content and humidity.23. How do good animal husbandry practices benefit farmers?

Ans. By animal husbandry, we mean scientific management of farm animals. Good animalhusbandry practices benefit the farmers in the following ways:

(a) Improvement of breeds of the domesticated animals.(b) Reduction of the input cost.

24. What are the benefits of cattle farming?

Ans. The main benefits of cattle farming are:(a) Wet milk from cattle and other milk products like butter, cheese, etc.

(b) Bullock labour is used for agricultural practices such as tilling, irrigation and carting.

25. For increasing production, what is common in poultry, fisheries and bee-keeping?Ans. Selection of improved varieties, housing, rearing, sanitation, disease control and management

offood.



Capture fishing Mariculture Aquaculture I

(a) It is the process of obtaining I t is a practice of culture of It is the production of fish fromfish from the natural marine fish varieties in the open freshwater resources like canals,resources like ponds, canals, sea. ponds, reservoirs, rIvers andrivers, etc. brackish water resources like

estuaries and lagoons.

(b) In capture fishing, fish can In mariculture. satellites and Like capture fishing, inbe located easily and then echo-sounders are used for aquaculture also the fish can becaught using fishing nets. locating fish. Then they are located easily and are caught

caught USLng man}' kinds of using simple fishing nets.fishing nets from the fishingboats.

1. Why is use of excess fertiliser determental for environment?

Ans. Fertilisers observing pre and post-application precautions for their compelte utilisation.Fertilisers get washed away due to excessive irrigation and are not fully absorbed by theplams. This excess fertiliser then leads to water pollution. Conditions use of fertilisers inan are can destroy soil fertility because the organic matter in the soil is not replenished andmicro-organisms in the soil are harmed by the fertilisers used.

2. List out some useful traits in improved crop?

Ans. Some useful traits in improved crops are:(i) Higher yield of crop

(ii) Improved quality of crop

(iii) Biotic and abiotic resistance

(iv) Change in maturity duration

(v) Wider adaptability and

(vi) Desiratble agronomic characteristics.

3. Arrange these statements in correct sequence of preparation of green manure.

(a) Green plants are decomposed in soil

(b) Green plants are cultivated for preparating manure or crop plant parts are used.

(c) Plants are ploughed and mixed in soil.

(d) After decomposition, it becomes green manure.

Ans. b ) C ) a ) d.

4. Discuss why pesticides are used in very accuracy concentration and in very appropriatemanner?

Ans. Pesticides include herbicides, insecticides and fungicides which are sprayed on crop plants orused for treating seeds and soil. However, excessive use of these chemicals creates problems,since they can be poisonous to many plam and animal species and cause environmentalpollution.

26. How do you differentiate between capture fishing, mariculture and aquaculture?

Ans.


EXERCISES

Very Short Answer Questions

1. Name any common weed found in a field.

2. Define a weed.

3. Name two fertilisers.4. Name one animal storage pests.

5. Name the nitrogenous fertilisers.6. Name one insecticide.

7. Write the full form ofEDCT

8. Name a green manure.9. Define venni-composting.

10. Name two varieties ofIndian fish.11. Mention one each of high milk-yielding varieties of cow and buffalo.

12. Write the full form of NDRI.

13. What is the role of roughage in cattle feed'14. Name four animals which provide us food.

15. Name any two Indian breeds of (i) cows, and (ii) buffaloes.

16. Mention the percentage of protein content in milk, egg and fish.

17. Write two high yielding varieties of poultry.18. Name any two animal diseases carried by bacteria and viruses.

19. How are goats and sheep useful to us?

Short Answer Questions

1. Write three sorts of precautions for handling pesticides.

2. Name two common weeds found in agricultural fields. Mention their control.

3. Name the factors responsible for grain loss during the storage of grains.4. What are pesticides? Name one pesticide.

5. Mention the improved cross-breeds of cow.

6. What do you mean by 'Operation Flood" Write any two responsible factors.

7. Define animal husbandry.8. Mention the salient features of a good shelter.

9. What is Silver Revolution?10. What are the major sources of our food'

11. Write two infectious diseases, each of cow, poultry and fish.

12. Define artificial insemination.13. Give three uses of animal husbandry.

14. Mention the names of animal products which are used as food.

15. How is cross-breeding useful in cattle?16. Mention three characteristics of a good animal shelter.

(1 mark)

(2,3 marks)

Long Answer Questions (5 marks)1. Name some improved storage structures for grain. Explain how grain is protected in these

structures.

2. Discuss various measures for safe storage of grains.

.. VK Biology IX 146 Improvement in Food Resources

(b) liver only

(d) adipocytes

3. Name one disease each of rice, wheat, mustard and sugarcane and suggest their controlmeasures.

4. Name two insect pests each of rice, mustard and sugarcane and suggest their control measures.

5. Define manures. What are the different manures and how do they affect the soil?

6. What are fertilisers? Classify fertilisers with suitable examples.

7. Define weeding. What tools are used for weeding?

8. What is green manuring? Give suitable examples for green manures.

9. ''\That is a fertiliser? How is it different from manure?

10. What are weeds? How are weeds controlled?

11. How are agricultural pests harmful?

12. What are crop pests? Suggest preventive measures to control pests.

13. Describe various measures for controlling insect pests in crops.

14. What are egg laying animals? Write the exotic breeds of poultry hen.

15. How would you protect the animals from various diseases?

16. How can we increase milk production in buffaloes and cows? Give names of improved breedsof cow and buffalo.

17. What measures have been taken to improve the production of food from animal sources inour country?

18. Milk production is meagre in India though there is a large population of cattle here. Why?

19. Mention few measures for prevention of diseases in the animals.

20. Briefly mention the advantages of artificial insemination. How is it done?

21. Name the different breeds of poultry bird. What is poultry farming?

Practical-based Multiple Choice Questions

1. Some food samples and their adulterants are given as followsI. Ghee (i) Orange dye

II. Milk (ii) Tamarind seeds

III. Coffee (iii) Starch

IV. Red Chilly (iv) Vanaspati

Four sequences of food samples and their correct adulterants are proposed from the abovecolumns. Which one of the following sequence is correct?(a) I - (i), II, (ii), III - (iii), IV - (iv)

(b) I-(iv), II - (iii), III-(ii), IV - (i)

(c) 1- (iv), II- (iii), III-(i), IV - (ii)

(d) I - (iii), II - (iv), III- (i), IV - (ii)

2. A Biology lab assistant was asked to prepare Iodine solution for starch test. He tried makingthe solution by mixing different chemicals in various ratios. Can you pick up the rightcombination from the following sets?(a) 2 g of Potassium Iodate in 100 mL distilled water

(b) I g ofIodine in 100 mL distilled water

(c) 1 g of Potassium Iodate + I g ofIodine ih lOa mL distilled water

(d) 2 g of Potassium Iodide + I g oflodine in lOa mL distilled water

3. Excess of glucose present in blood is converted into glycogen in the presence of insulinhormone. Glycogen is stored in(a) muscles only

(c) both a and b


(i) Cane sugar

(ii) Apple

(iii) Milk

(iv) Blood sugar

4. Four students, studying biochemistry for the first time, decided to perform the confirmatorytest for the presence of starch on potato slices. Since they were not sure of the chemicalwhich could give the blue black colour with starch, they tried their hands with differenttypes. Only one of them gave the correct result which can be identified as

(a) fluorine (h) chlorine

(c) iodine (d) bromine

5. Match the pair correctly.I. Glucose

II. Sucrose

III. Fructose

Iv. Lactose

(a) I - (iv), II - (i), III - (ii), IV-(iii)

(h) I - (i), II - (ii), III - (iv), IV - (iii)

(c) I - (iv), II - (iii), III - (ii), IV -(i)

(d) I - (ii), II-(i), III - (iii), IV - (iv)

6. An experiment was performed in Class IX to demonstrate the effect of denature agents onenzymes by taking different chemicals in 5mL starch solution. 15 minutes later, the tubeswere tasted for the presence of starch with the help oflodine. One ofthe tubes did not givethe blue black colour in the test tube because

5 mL starch solution+ 1 mL Hel

+ 1 mL ptylin

(A)

5 mL starch solution 5 mL starch solution 5 mL starch solution+ 1 mL alcohol + 1 mL ptylin + 1 mL water+ 1 mL ptylin

(B) (C) (D)

(a) tube A as ptyalin was denatured

(h) tube B as starch was destroyed with alcohol

(c) tube C as ptyalin changed starch into maltose

(d) tube D as starch solution was diluted by adding water

7. Which of the following chemical is used to observe the presence of starch in the foodextract?(a) 12 solution (Iodine) (h) Cone. HCl

(c) Benedict's reagent (d) None of these

8. Substance 'X' was added to a test tube containing water and grounded arhar dal to test thepresence of metanil yellow. The colour of solution changed to pink. Identify 'X'.(a) Hp (h) l\aOH

(c) H2C03 (d) HCl

9. A student added only two drops of iodine to a rice extract in test tube A. Another studentadded a little rice extract to iodine solution in test tube B. They would then observe(a) a change of colour to blue black in test tube A but not in test tube B

(b) a change of colour to blue black in test tube B but not in test tube A


(e) a change of colour to blue black in Doth test tubes A and B

(d) no change of colour in any test tube

10. Paul was rushing with a bottle of tincture iodine. Some iodine solution splashed on hisyellow coloured cotton shirt and also on the white table cloth. The stain on the table cloth .was yellowish brown while that on his shirt was blue black. The most plausible scientificreason for this is that the(a) Shirt was dyed with metanil yellow

(b) Shirt was starched after washing

(e) Table cloth was starched but not the shirt

(d) Shirt had absorbed sweat

II. Four samples of arhar dal (tuvar dal) were taken in four test tubes with some water in eachand labelled P, Q, Rand S. A few drops of the following were added to these test tubes:water to test tube P, HCI to test tube Q, NaOH to test tube R and alcohol to test tube S. Wewould be able to confirm adulteration of the dal with metanil yellow in test tubes(a) P and Q (b) Qand R

(e) Rand S (d) Sand P

12. The teacher asked the student to correctly record results of the experiment done to detectpresence ofmetanil yellow in the adulterated arhardal (tuvar dal) sample that was providedto them.

S.No. Procedure Observation Inference

A 5g da! + 5 g metani! yellow Dal turns yellow Metani! yellow present

B 5 g dal + 5 mL'water Solution turns pink Metani! yellow present 111

+ 2 drops ofHCI the sample

C 5 g dal + 5 mL water ,.vater turns yellow Metanil yellow present+ pinch of metanil yellow

D 5 g dal + 5 mL water Metanil yellow present Water turns yellow and then+ 2 drops of HC[ pink

The correct recording of the experiment is done in table(a) A (b) B

(e) C (d) D

13. On the laboratory table were placed four watch glasses with labels A, B, C and D. Watchglass "A" had chalk powder, "B" had sago powder, "C" had common salt and "D" hadpowdered sugar. On adding two drops of iodine to the content of each watch glass, the oneturning blue black will be(a) A (b) B

(e) C (d) D

14. Seema bought arhar dal (tuar dal) from the market. On adding water to the dal the waterbecame yellow in colour. She took a sample of this yellow water to the laboratory and addeda few drops ofHCI. The sample became pink. This confirmed that the adulterant added tothe dal was(a) turmeric (b) metani! yellow

(e) potassium dichromate (d) yellow dye

15. To observe starch granules in potato under a microscope, freshly cut surface of potato waspressed on a slide. The stain that will show starch granules clearly is(a) methylene blue (b) iodine

(e) safran in (d) eosin

1-_t-...,;;lm;;:p;:.ro:.;v.:.;em;:.e;:.n.:.;li;:.n;:.Fo:.;O.:.;d;:.Re;;;so.:.;u;;,;rc;;;es=-- ;:.[;:.4.:....9liilii.:iil~;ii;l,t_---.

(b) Shreya(d) Chitra

16. A very fast driver of a motorcycle met with an accident that resulted in heavy bleeding. Assoon as he was rushed to the hospital they put him on intravenous 5% dextrose sugar. Whatis the other name of this sugar that is the instant source of energy?(a) Fructose (b) Glucose(e) Sucrose (d) Lactose

17. Identify the plant from the following that is not a pulse.(a) Mustard (b) Pea

(e) Groundnut (d) Blackgram

18. An infant suffering from PEM disorder, Kwashiorkor was advised to have protein rich milkprepared from one ofthe legumes. Identify the source.(a) Groundnut (b) Arhar dal

(e) Moong dal (d) Soyabeen

19. Which one does not correctly provide us starch grains found in the specific food stuff?(a) Potato (b) Banana

(e) Wheat (d) Rice

20. Which is the most abundant carbohydrate found on earth?(a) Starch (b) Glycogen(e) Chitin (d) Cellulose

21. From the following carbohydrates, find out the one, that is insoluble in water.(a) Starch (b) Glucose

(e) Fructose (d) Insulin

22. In slimming centres like VLCC, obese patients are advised not to have excess of certainnutrients but the restriction is not imposed on patients for one type of carbohydrates.Identify it.(a) Fats (b) Starch

(e) Sucrose (d) Cellulose

23. A class IV student was having veg biryani during the break. A senior scolded him.

Scared of his senior, he immediately ran to his elder brother who was a class XI student andwas performing an experiment in chemistry lab with Iodine solution and collided with hiselder bother, The solution spilled on biryani and changed its colour to blue black because(a) biryani is made from wheat which has starch in it(b) biryani is made from rice which has starch in it

(e) biryani is made from pulses which has starch in it

(d) iodine is already having blue black

24. Which of the following statements is incorrect?(a) A 40 years old gardener should be given lots of carbohydrate

(b) A 5 year old child should be given lot of proteins and carbohydrates

(e) A pregnant mother should be given lot of fats to get energy(d) A sick person should be given soft diet having proteins vitamins & minerals

25. Four students of Central School, Noida were provided with adulterated pulses to test thepresence of metanil yellow. They all added 5mL of water to 5g of pulses but forgot thename of the acid that gives magenta colour with the adulterant. Sanjeevani, Shreya, Alkaand Chitra added few drops of cone. , cone. , cone. HCI and respectively. Who accordingto you had added the right acid?(a) Sanjeevani

(e) Alka

0.'


26. Observe the following tubes carefully.

5 mL sugarcanejuice + 2 mL fehllng (A)

and fehling (8)

(i)

5 mL apple juice+ 2 mL fehling (A)

and fehling (8)

(ii)

5 mL grape juice+ 2 mL fehling (A)

and fehling (B)

(iii)

5 mL orange juice+ 2 mL fehling (A)

and fehling (8)

(iv)

(b) (ii)

(d) (iv)

On heating all these test tubes one of them would not give a red precipitate with Fehling'ssolution though all of them contain sugar. Which of the following tube will not give redprecipitation?(a) (i)

(e) (iii)

Answers

1. (b) 2. (d) 3. (e) 4. (e)

5. (d) 6. (e) 7. (a) 8. (d)

9. (e) 10. (b) 11. (a) 12. (b)

13.(b) 14. (b) 15. (b) 16. (b)

17.(a) 18. (d) 19. (b) 20. (d)

21. (a) 22. (d) 23. (b) 24. (e)

25.(e) 26. (a)

III


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