The National Anthem - Education Observer

The National AnthemJana-gana-mana adhinayaka, jaya he

Bharatha-bhagya-vidhata.Punjab-Sindh-Gujarat-Maratha

Dravida-Utkala-BangaVindhya-Himachala-Yamuna-Ganga

Uchchala-Jaladhi-tarangaTava subha name jage,Tava subha asisa mage,Gahe tava jaya gatha.

Jana-gana-mangala-dayaka jaya heBharatha-bhagya-vidhata.

Jaya he, jaya he, jaya he,Jaya jaya jaya, jaya he!

PledgeIndia is my country. All Indians are mybrothers and sisters.I love my country, and I am proud of its richand varied heritage. I shall always strive tobe worthy of it.I shall give respect to my parents, teachers andall elders and treat everyone with courtesy.I pledge my devotion to my country and mypeople. In their well-being and prosperityalone lies my happiness.

Dear Students,

Science is activity based. Its method is the unprejudiced investigation oftruth, based on scientific evidence. If what is generally considered righttoday is scientifically proved wrong tomorrow, it would be accepted. Thisis how Science works. This rational method has to be employed in learningScience. Continuous observations, experimentations and analyses leadthe scientific perspectives to new dimensions. Hence, you have to makeuse of every possible opportunity to observe and experiment.

The student’s role is pivotal in the process of construction of knowledge.This Science textbook is only a resource in the learning process. Yourteachers and supplementary materials will help you in the creation ofknowledge. 'Samagra', the education portal and technology enabled Q RCode printed textbooks would definitely make your learning activity inclassrooms easy and joyful.

The National Skills Qualifications Framework, the current relevance ofDisaster Management and the possibilities of I.C.T. have also beenconsidered in the textbook.

This book includes lessons which spread light on Photosynthesis, thebasis of existence of the living world, the diverse Organ systems of thehuman body, the complex Life processes they perform, Cell divisionwhich leads to the growth of the body and the Science behind maintainingthe uniqueness of living species.

The method of presentation adopted is centred in the life processes thatwould be conducive to the learner to achieve Life skills and Health habits.Learning experiences which provide knowledge and delight have beenincluded here. We expect the textbook to be helpful in the further learningof Science.

Love and Regards,Dr. J.Prasad

DirectorSCERT, Kerala

State Council of Educational Research and Training (SCERT)Poojappura, Thiruvananthapuram 695012, Kerala

Website : www.scertkerala.gov.ine-mail : [email protected]

Phone : 0471 - 2341883, Fax : 0471 - 2341869Typesetting and Layout : SCERT

Printed at KBPS, Kakkanad, Kochi-30© Department of Education, Government of Kerala

For further reading(Evaluation not required)

Let us Assess

Extended Activities

Certain icons are used in thistextbook for convenience

A poster designed by Sangeeth for a poster designing competition basedon the message ‘save earth from global warming’, is presented above. Whatinferences can you formulate from this poster?

You have heard about global warming. It is a dangerous phenomenonwhich leads to the rise in earth’s temperature. The main reason for globalwarming is the increase in the level of carbon dioxide in the atmosphere.Plants can resist this to a certain extent. Analyse illustration 1.1 given belowbased on the indicators and prepare notes in the Science diary.

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Biology ̨ IX

Why is the upper part ofleaf greener than the lower part?

Indicators

• Why doesn’t the level of oxygen in the atmosphere decrease?

• Why doesn’t the level of carbon dioxide in the atmosphereincrease?

• Which process in plants regulate the level of oxygen andcarbon dioxide in the atmosphere?

Have you understood how plants control global warming?

List out the factors, other than carbon dioxide that are requiredfor photosynthesis.• Minerals and salts •• •Where do plants acquire these factors from? Discuss.

Have you noticed Thara’s doubt? Visitthe biodiversity park of your school andexamine the validity of the doubt.

Pigments in Leaves

You know that chlorophyll impartsgreen colour to plant parts. With thehelp of your teacher, observe the sectionof a leaf through a microscope. Based onthe indicators, analyse illustration 1.2and description and formulate yourinferences.

PlantsPlantsPlantsPlantsPlantsRespiration

Animals AtmosphereO2

Glucose

Atmosphere CO2

Illustration 1.1Oxygen - carbon dioxidebalance in atmosphere.

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Biology ̨ IX

Plant cell

Section of leafVascular tissue

Stomata

Grana (pack ofmembranous sacs)

Epidermis

Double membrane

Stroma(fluid part ofchloroplast)

Chloroplast

Illustration 1.2 Structure of chloroplast

Photosynthesis takes place in chloroplast. It occurs not only in leaves, but in regionswherever chloroplast is present. Pigments that absorb sunlight are found in thegrana of chloroplast. Chlorophyll a, chlorophyll b, carotene and xanthophyll arethe pigments present in grana. All these pigments can absorb sunlight. However,only chlorophyll a can participate directly in photosynthesis. All other pigmentsabsorb light and transfer it to chlorophyll a. Hence they are called accessory pigments.

Indicators

• Parts of chloroplast.

• Pigments in chloroplast.

• Role of pigments in photosynthesis.

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Biology ̨ IX

Light phase

Chloroplast

• Light is not used.

• Energy in ATP is used tocombine hydrogen andcarbon dioxide to produceglucose.

• Light is used.

• Water splits and oxygen is released.Hydrogen reaches stroma.

• Light energy is converted tochemical energy and stored in ATP.

Illustration 1.3 Phases of photosynthesis

Grana Stroma

Dark phase

Path of carbon dioxideto leaves

Path of water to leaves

Inside the leaves

Root

Atmosphere

The Chemistry of Photosynthesis

How do plants produce food and oxygen through photosynthesis?Observe illustration 1.3, compare the two phases ofphotosynthesis and complete table 1.1.

Along with carbon dioxide, water should also reach the leavesfor photosynthesis. How do they reach the leaves? Complete thework sheet.

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Biology ̨ IX

Table 1.1

Indicators Dark phaseLocation

Action

Products

Necessity of light

ATP Formed Utilized

Light phase

Sunlight.................. + ..................

Chlorophyll.................. + ..................

Illustration 1.4

The complex process involved in photosynthesis was unfoldedafter long years of study and experimentation by many scientists.Photosynthesis remains an aspiring area of research even today.Prepare a Science edition by collecting information aboutresearch activities in this area.

Energy currenciesAvailability of energy must be ensuredfor continuous metabolic activities inthe cells. ATP (Adenosine triphosphate)molecule is used for the continuoustransfer of energy. The energy liberatedduring the break down of ATP into ADP(Adenosine diphosphate) and phosphateis used for the metabolic activities.ADP restores energy and gets convertedback to ATP. Since such energytransaction is done by ATP, it is knownas the energy currency of the cell.

Dark phase follows the light phase.The cyclic chemical reactions in thedark phase were discovered by thescientist MelvinCalvin. Hence,this phase isknown as Calvincycle. He wasawarded theNobel Prize in1961 for this discovery.

Now you have understood thechemical reactions in the process ofphotosynthesis. Based on this,complete illustration 1.4 given below.

Melvin Calvin

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Biology ̨ IX

Starch(Tubers)

Protein(Legumes)

Fat(Oil seeds)

Fructose(Fruits)

Sucrose(Sugarcane)

Illustration 1.5 Chemical changes in glucose

If glucose is what all plants prepare, thenhow could we get starch, protein and fat

from vegetable food items?

After Photosynthesis

Isn’t Beena’s doubt genuine?

What happens to the glucoseformed as a result ofphotosynthesis? Analyse thedescription and illustration 1.5given below. Based on youranalysis, prepare a note on thechemical changes of glucose inplants in the Science diary.

Since glucose is easily soluble in water it cannot be storedin plant body. Therefore, plants store glucose in the form ofinsoluble starch in leaves. Plants utilize starch as a sourceof energy for life activities and to prepare substancesrequired for growth. Starch is later converted to sucroseand is transported through phloem to various plant partsand stored there in different forms.

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Biology ̨ IX

ChemosynthesisAll producers on earth do not dependon sunlight. The sulphur bacteria seenon land and in water are examples forthis. They produce energy by breakingdown chemical compounds. Thisprocess is called chemosynthesis.

Figure 1.1 Products of economic importance.

Indicators

• Need of converting glucose to starch.

• Methods by which plants utilizestarch.

• Storage of food in different parts ofthe plant.

Have you understood how various typesof nutrients required for animals areobtained from plants?

Do plants provide only food and oxygen?Observe the figures 1.1 given below and find more examples.

Most plant parts have economic importance in one way or theother. A variety of value added products are made from them.The processing and marketing of these resources open doors toa wide range of job opportunities. With the help of your teachercollect information about economically important plantresources. Organize a discussion in your class on the jobopportunities related to this area. Have you understood howdiverse the plant world is?

Ocean at par with Land

Ocean is far more extensive than land. Ocean too has an amazingdiversity in its ecosystem. Small organisms to the giant whaleslive there.

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Biology ̨ IX

Algae and PhytoplanktonsThe world of algae is diverse. Based on the quantityof the main pigment present in them, algae maybe green, red or brown in colour. Algae are diversein their size too; from microscopic size to metreslong. Sargassum is a large brown algae.Phytoplanktons found in oceans are free floatingmicroscopic organisms that performphotosynthesis. Desmids, golden algae andcyanobacteria are examples of phytoplanktons.

Algae andwater plants

Birds andanimals

Fishes and otherorganismsOxygen

Food

Illustration 1.6Ocean as an ecosystem

Phytoplanktons

Oxygen

Analyse illustration 1.6 and the description given below. On thebasis of the analysis and the indicators provided, discuss and writedown your inferences in the Science diary.

Oxygen is essential for the existence of organisms. You know thatoxygen in the atmosphere is obtained through photosynthesis.About 70-80 percent of oxygen in the atmosphere is contributedby algae and phytoplanktons present in the sea.

Indicators

• Chief producers inthe ocean ecosystem.

• Importance ofphotosynthesis inocean.

Ocean gets polluted due tovarious reasons. Find itsreasons and prepare ashort note.

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Biology ̨ IX

Like land pollution, ocean pollution also adversely affectsorganisms including human beings. What can we do to avoid this?Formulate suggestions.

Plants - Earth's Wealth

The service rendered by plants for the sustenance of the livingworld is unique. Plants serve as the cheapest, effective and naturalmeans for the purification of air. By absorbing carbon dioxidefrom the atmosphere and releasing oxygen, plants provideinvaluable service to the living world. Plants also have a majorrole in the mitigation of natural disasters.

It is not when natural calamities happen that one should thinkabout nature conservation. Nature conservation should becomepart and parcel of everyone's life. Nature should be used wiselyand preserved for the generations to come. Green plants are theprotectors of biosphere. Hence for the conservation of nature,nurturing of plants should be considered as one's primeresponsibility.

Mangrove forests helpin controlling Tsunamito some extend.Bamboo forests, reed,vetiver, lemongrass etc.protect the river banksfrom collapsing duringflood. Trees and bushesin mountains and hillsprevent soil erosionand landslide.

Mangroveforest

Vetiver

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Biology ̨ IX

Plant part Stored form of glucose

1. Which of the pigments given below participate directly inphotosynthesis?

A. Chlorophyll a

B. Chlorophyll b

C. Xanthophyll

D. Carotene

2. Glucose formed as a result of photosynthesis gets stored indifferent parts of the plant in different forms throughmetabolic activities. Based on this, complete the table givenbelow.

3. Diagram showing the structure of chloroplast is given below.Redraw the diagram and label its important parts.

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Biology ̨ IX

Light energy

Carbon dioxideGlucose

Water

Oxygen

4. Correct the statements given below by replacing theunderlined words alone, if found incorrect.

a. Oxygen is formed during photosynthesis by the splittingof carbon dioxide.

b. The dark phase of photosynthesis takes place in thestroma.

c. Glucose is transported through the phloem tube tovarious parts of the plant.

5. Plants are the lungs of earth. Assess the relevance of thisstatement and prepare notes.

1. Collect the green algae named Spirogyra. Observe it throughthe microscope with the help of your teacher and identifythe shape of chloroplast.

2. Observe the illustration of photosynthesis. Prepare similarillustrations and exhibit them in the classroom.

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Biology ̨ IX

3. Arrange an experimental set up as shown in the figure.Observe the difference in the evolution of gas when sunlightfalls directly and indirectly and write your inferences in theScience diary.

4. Analyse the illustration given below. Collect informationregarding the reasons for global warming, its consequencesand remedial measures, and with the help of a presentationconduct a seminar in the classroom.

Adithyan is reading a question from the doubt box maintainedby the Science club. What reply can you give? Write in the Sciencediary.

We get nutrients required for life activities from the food we eat.Complete table 2.1 by including their functions.

Plants which prepareand use food by themselves do

not have a digestive system.Then why do we, who receive

food from plants have adigestive system?

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Biology ̨ IX

Figure 2.1 Human digestive system

Carbohydrate

ProteinFatMineralsVitamins

Water

Nutrient Function

Table 2.1

You know that the food materials we eat are not absorbed as suchby our body. Digestion is the process of converting complex foodmaterials into simple absorbable forms.

Examine figure 2.1. Identify and label the parts of the digestivesystem.

Food inside Mouth

What changes happen to food inside the mouth?

•• Mixes with saliva.

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Biology ̨ IX

Molar..................................

..................................

Premolar..................................

.....................................

Canine.............................................

.............................................

IncisorHelps to bite and cut thefood

Illustration 2.1 Different types of teeth

MolarCanine

Illustration 2.2 Structure of molar tooth.

Crown

Neck

Root

Crown

Neck

Root

Enamel: White in colour, thehardest part, dead tissue.

Dentine: Living tissue whichforms the tooth.

Pulp: Soft connective tissueseen in the pulp cavity. Bloodvessels, lymph ducts and nervefibres are also seen.

Cementum: Calciumcontaining connective tissuethat holds the tooth in thesocket of the gum.

The structure and arrangement ofteeth is suitable to masticate the foodwe eat. Complete the missing areasin illustration 2.1 regarding thearrangement of teeth.

Eventhough teeth vary in theirmorphology and function, they showsimilarities in their internal structure.

Compare the completed illustration2.1 and 2.2, analyse and preparenotes on the internal structuralsimilarity and functional differenceof teeth.

You have understood how the structure of teeth is suitable to breakdown food materials to smaller particles. What is the role oftongue in this process?

The tongue helps teeth to masticate food materials and mix themwith saliva. The taste buds in the tongue help in the sensation oftaste. Now you have understood the necessity of protecting teethand tongue which help in masticating and moving food into thefood pipe. Discuss the habits for achieving this and prepare a noteon the same.

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Biology ̨ IX

Closes the nasalcavity that opens to

the pharynx.

Posterior part ofthe tongue allowsfood to move overthe epiglottis intothe oesophagus.

Tongue compresses the food into ballswith the help of the palate.

Illustration 2.3 Mode of swallowing food

Uvula

Trachea rises up andis closed by this

part.

Epiglottis

Saliva and Digestion

Our mouth waters the moment we think oftasty food. Where is saliva produced? Doessaliva play any role in the process of digestion?Note down your assumption.

There are three pairs of salivary glands in themouth (Figure 2.2). The saliva secreted fromthe salivary glands contains mucus and

enzymes like salivary amylase and lysozyme. Mucus makes thefood slimy, so that it can be swallowed. Lysozyme, to an extent,helps to destroy the germs that enter the body through food.Salivary amylase partially converts starch to maltose, a form ofsugar.So you have understood the chemistry behind the sweet tastewhile chewing rice for a certain time without adding curry.

Food through Oesophagus

Partially digested food enters oesophagus through the pharynx.You know that trachea also begins from pharynx.

How does the food that we swallow enter exactly into theoesophagus without entering the trachea? Analyse illustration2.3 and prepare a note.

Figure 2.2 Salivary glands

Salivaryglands

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Biology ̨ IX

Figure 2.4 Peristalsis in the stomach

Circularmuscles

Oesophagus Stomach

Figure 2.3 Peristalsis in the oesophagus

Have you understood the relevance of the saying that one shouldnot talk while having food?

You know that food reaches the stomach by the wave likemovement of the walls of the oesophagus. These movements arecalled peristalsis.

Food inside the Stomach

The slightly digested food in the mouth reaches the stomach,where further digestion takes place. On the basis of indicators,and the description, analyse figure 2.4 and illustration 2.4 andprepare notes on the digestive process in the stomach.

The strong peristalsis in the stomach converts food into a pasteform. The special circular muscles present in the posterior partof the stomach retain food for a specific period. Differentcomponents in the gastric juice, secreted by the glands in thestomach wall also play a very important role in the process ofdigestion.

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Biology ̨ IX

Gastricjuice

Hydrochloricacid

Mucus

Pepsinenzyme

Converts protein topeptones partially.

Digests fat partially.

Destroys germs in the food.Regulates pH suitable for thedigestion in stomach.Protects the stomach wallfrom the actions of digestivejuices.

Illustration 2.4 Gastric juice –Components and functions

Gastriclipase

enzyme

Acid factory of the bodyThe oxyntic cells present in the stomachwall produce hydrochloric acid, a maincomponent of the gastric juice. Its pHvalue ranges from 1 to 3. Why this acidwhich can dissolve even metals does notharm the stomach wall is a relevantquestion. The special cells present in theepithelial tissues secrete mucus andbicarbonate which protect the stomachwall. The mucus covers the inner wall ofthe stomach and protects it. The alkalinebicarbonate neutralizes the acid. But insome persons the production of acidbecomes excessive and the securitysystem fails. Acidity can become a healthissue. If acidity persists it becomesgastric ulcer.

Indicators

• Role of the muslces in thestomach wall in digestive process.

• What is the role of non-enzymecomponents of the gastric juice?

• Which are the nutrients thatundergo digestion inside thestomach. How?

Food in the Small IntestineHuman small intestine is about five tosix metres long. It is found in theabdomen in the form of multiple foldsand coils. Hence food moves veryslowly through the small intestine.

The completion of digestion and thebeginning of absorption of food takesplace in the small intestine. From thestomach, the food in paste form enters

the duodenum which is the initial part of the small intestine. Thedigestive juices secreted by the liver and the pancreas reachduodenum through a common duct. The enzymes in these juicesact upon the partially digested food and enhance the process ofdigestion. Analyse illustration 2.5 and frame inferences on therole of liver in the process of digestion.

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Biology ̨ IX

Table 2.2

Pancreatic amylaseMaltose

TrypsinPeptide

Pancreatic lipaseFatty acid + Glycerol

Pancreatic juice

Starch

Protein

Fat

PancreasSecretes pancreatic juice. Bile and thepancreatic juice reach the duodenumthrough a common duct.

LiverEnzymes are absent in the bile secretedby the liver. It helps in digestion bybreaking down fat into smaller particlesand making the food alkaline. The bilesecreted by the liver is stored in the gallbladder.

Illustration 2.5 Liver and Pancreas

Gall bladder

Duodenum

Commonduct

Have you understood the role of bile in digestion eventhoughenzymes are absent in it? Observe the flow chart given belowand prepare a note on how enzymes in pancreatic juice help inthe digestion of nutrients.

When food moves forward from duodenum, it gets mixed withthe intestinal juice secreted by the glands in the small intestine.Different enzymes are present in the intestinal juice, some ofwhich convert maltose, lactose (the carbohydrate in milk) andsugar (sucrose) into simpler forms like glucose, fructose andgalactose. Another set of enzymes converts peptides to aminoacids. You know that the digestion of fat is almost completed inthe duodenum itself. If so, which are the end products formed afterdigestion? Write in table 2.2.

Nutrients subjected to digestion End products

Carbohydrate

Protein

Fat

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Biology ̨ IX

LactealFatty acid andglycerol are

absorbed into thelymph of lacteal.

Illustration 2.6 Position and structure of villusBranch of artery

Branch of vein

Villus Blood capillariesGlucose, fructose,

galactose andamino acid are

absorbed into blood

Lymph duct

Now you have understood that digestion is the process ofconversion of carbohydrate, protein and fat which have complexstructures into easily absorbable simpler forms. Which are thenutrients that do not undergo digestion?• Water••

What could be the reason for this? Discuss and write yourinference in the Science diary.

Absorption begins

The absorption of simple nutrients begins in the small intestine.How far is the structure of small intestine suitable for this?Analyse illustration 2.6 and the description given. Prepare notesin your Science diary.

Villi are small finger like projections seen in the walls of theintestine. These increase the surface area of absorption ofnutrients to a great extent within the small intestine. Villi arecovered with a single layer of cells. They also contain bloodcapillaries and lacteals, the lymph capillaries. Water solublesimple nutrients are absorbed into the blood. You can assume whyfatty acids and glycerol are not absorbed into the blood.Absorption of nutrients and 90 percent of water take placethrough villi.

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Biology ̨ IX

Figure 2.5 Diffusion

Higherconcentration Equal concentration

Lowerconcentration

Indicators

• Length of small intestine and structure of villus.• Villi and surface area of absorption.• Absorption of simple nutrients into the blood.• Absorption of simple nutrients into the lymph.

You have understood that simple nutrients are absorbed into theblood and lymph through the walls of blood capillaries andlacteals. The cells in these walls also play a role in this process.There are certain processes working behind the movement ofmolecules in and out of the cell. Based on the indicators, analysethe description given below and write notes in the Science diary.

Behind AbsorptionAbsorption of simple nutrients from the small intestine takes place alongand against the concentration gradient. Simple diffusion, facilitateddiffusion and osmosis are movements of molecules from a region ofhigher concentration to a region of lower concentration. As theseprocesses take place along the concentration gradient, energy is notrequired.Simple diffusion and facilitated diffusionObserve figure 2.5. Haven’t you noticed the movement of moleculesfrom a higher concentrated region to a lower concentrated region?Did you notice upto which stage this flow continues? This is calledsimple diffusion.

The absorption of fatty acid and glycerol to lacteal takes place by simplediffusion. Diffusion can also take place without a semi permeablemembrane. Spread of odour in air and spread of ink in water are alsodiffusion.The diffusion of some molecules takes place with the help of proteinmolecules present in the cell membrane. This is facilitated diffusion.

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Biology ̨ IX

The absorption of glucose, fructose, galactose and some amino acidsinto the blood capillaries takes place by this process.OsmosisAbsorption of water takes place by osmosis. Osmosis is the movementof water molecules from a region of higher concentration to a regionof lower concentration through a semi permeable membrane.Though this happens along the concentration gradient, this is applicableonly to water molecules.Active transportIn some instances absorption takes place against the concentrationgradient. Molecules are absorbed from a region of lowerconcentration to a region of higher concentration by utilising energyand with the help of carrier proteins. This process is called activetransport.When the concentration of glucose, salts etc. decreases in the smallintestine, absorption takes place by active transport. Thus, based onthe requirement of the cell, maximum glucose and salts enter bloodwithout any loss.

Indicators

• Processes which help in the absorption of simple nutrients.• Differences and similarities between simple diffusion,

facilitated diffusion and osmosis.

• Absorption of glucose.

In and out of the Large Intestine

The digestive wastes left after the absorption of nutrients movetowards the large intestine. A major portion of the salts and waterleft after the absorption in the small intestine are absorbed in thelarge intestine. Certain bacteria residing in the large intestineproduce substances like vitamin K. Absorption of these substancesalso takes place in the large intestine. Subsequently, the digestivewastes stored in the rectum are eliminated out through the anus.The process of digestion is completed through various complexprocesses taking place in the digestive tract. It requires about 4-5hours. Hence it is necessary to regulate the intake of foodaccordingly.

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Biology ̨ IX

Has the doubt raised by Adithyan in the beginning of this chapterbeen clarified? In light of the new knowledge, modify the answeryou wrote in the Science diary, if required. Digestion is the processof conversion of complex nutrients into simple and easilyabsorbable forms. But plants prepare glucose, which itself is asimple nutrient. So it need not undergo further digestion.

A graffiti prepared to show the relationship between food andhealth is given below. Analyse the graffiti and the child's responseon the basis of indicators, collect additional information andconduct a seminar.

Indicators for gathering information

• Importance of roughage for a healthy digestive system.

• Health issues created by junk food and fast food.

• Harmful chemical substances added to food to enhance itstaste and colour.

Selecting food items by giving importance to taste can be harmfulto health. Though fibre content in cereals and vegetables do notundergo digestion, they help in the absorption process, easedefecation and thus protect the health of the digestive system.Health through food should be our motto because health of theindividual is the foundation stone for the progress of society.

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Biology ̨ IX

1. Identify the correct statements related to bile.

a) Produced in liver

b) Enzymes are found

c) Secreted into the stomach

d) Breaks down fat into tiny particles

2. Complete the table related to the process of digestion inhumans.

Part of digestive tract Enzyme Action

Mouth ....................... Starch Maltose

....................... Pepsin .......................

Small intestine Trypsin .......................

....................... Pancreatic lipase .......................

3. How does the structure of the small intestine help inincreasing the surface area of absorption?

• Construct the model of a tooth showing its internal structureusing available materials and exhibit it in the classroom.

• With the help of your teacher and dietician, identify thenutrients present in food. Acquaint yourself with thesymptoms of lifestyle diseases and deficiency diseases,suggest preventive measures.

• Through a health survey find out the unhealthy food habitsin children and adults and prepare a survey report.

Simple nutrients reach cellsthrough blood. If so, does blood

enter cells?

Does it...?

Don't you have doubts like these? Do simple nutrients get absorbedinto the blood and lymph in the small intestine? Let’s modify thedoubt raised by Sabu and Sini.

How do simple nutrients reach the cells through bloodHow do simple nutrients reach the cells through bloodHow do simple nutrients reach the cells through bloodHow do simple nutrients reach the cells through bloodHow do simple nutrients reach the cells through bloodand lymph?and lymph?and lymph?and lymph?and lymph?

Is the structure of blood suitable to carry substances?

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Biology ̨ IX

AlbuminRegulatesbloodpressure

GlobulinHelps indefence

FibrinogenPlays a major rolein the coagulationof blood

Fat Salts Urea Sugar Hormones

etc.

Plasma

Water(upto 90-92%) Proteins (upto 7-8%) Other factors

Illustration 3.1 Components of plasma

Plasma(55%)

Blood cells(45%)

Figure 3.1Components

of blood

To know this, we must understand the components of blood.You know that blood contains plasma and blood cells. But,they cannot be distinguished in a single glance. Let’sfamiliarise ourselves with an experiment to understand this.

If you add chemicals like EDTA (Ethylene Diamine TetraAcetic acid) which is an anticoagulant of blood, to a testtube containing blood, and wait for sometime, we canobserve blood cells and the liquid part of the blooddistinctly as shown in figure 3.1.

Blood cells constitute 45% of blood. List the various typesof blood cells.

••• PlateletsEventhough blood cells perform various functions, plasma playsa major role in the transport of simple nutrients.

PlasmaPlasma is the pale yellow coloured fluid that constitutes 55% ofblood. Blood cells are found in the plasma. The simpler moleculesformed as a result of digestion, namely glucose, amino acids, fattyacids, glycerol etc., reach cells through the plasma. With the helpof the indicators, analyse illustration 3.1 given below, and preparea note on plasma.

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Biology ̨ IX

Figure 3.3 Longitudinal section of the heart

Hints :Direction ofblood flow.

Valves prevent thebackward flow ofblood.

Right ventricle

Tricuspid valve

Inferior venacava

Right pulmonary artery

Superior venacava

Right atrium

Left pulmonary artery

Left pulmonaryveins

Left atrium

Left ventricle

Aorta

Bicuspid valve

Pulmonaryvalve

Aorticvalve

Right pulmonaryveins

Pulmonary artery

Figure 3.2 Position of heart

Indicators

• Factors absorbed through plasma.

• Plasma proteins and their functions.

You know that the blood circulates all over the body through bloodvessels. But, are blood vessels alone sufficient for this?

Heart

As the human heart works relentlessly like a pump,blood flows through blood vessels continuously inall directions. The heart is situated slightly tiltedtowards the left in between the two lungs, behindthe sternum in the thoracic cavity (Figure 3.2). Thesize of the human heart is equal to the size of one'sfist. Pericardium is a double layered membrane thatcovers the heart. Pericardial fluid is filled in betweenthe pericardial membranes. This fluid helps to reduce frictionbetween the membranes when the heart beats.

Based on the indicators, analyse figure 3.3 given below andprepare a note.

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Biology ̨ IX

Elastic outercovering

Muscular layers

Muscular layers

Valve

Elastic outercovering

Vein

carries blood to the heart. thin wall. valves are seen inside. blood flows with low speed and

low pressure.

Artery

carries blood from the heart. thick and elastic walls. blood flows with high speed

and high pressure.

Capillaries

thin vessels that connect veins andarteries together.

wall is formed of a single layer of cells. minute pores on the walls. valves are absent. blood flows with low speed and low

pressure.

Illustration 3.2 Various kinds of blood vessels

Artery

Capillary

Vein

Figure 3.4 Blood vessels

Indicators• Chambers of the heart.• The blood vessels which carry blood to the heart and the

heart chambers where they end.• The blood vessels which carry blood from the heart and the

heart chambers from where they begin.• Valves - position, function.

Have you understood that along with the heart, theblood vessels also have a role in circulating blood todifferent parts of the body? Large arteries arising fromthe heart, split into small arteries and these in turn splitinto capillaries. Further, these capillaries unite to form

small veins and these small veins unite to form larger veins andfinally reach the heart. Blood vessels are of 3 types.

Observe illustration 3.2 to know more about blood vessels. Basedon the indicators, compare the blood vessels and complete table3.1.

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Biology ̨ IX

Right atrium ................ (1)

....... valve(2)....... valve(3)

.................... (4) Left ventricle

.................... (5) Aorta

Venacavae Pulmonary veinsBlood from different

parts of the bodyBlood fromthe lungs

Blood to thelungs

Blood to different partsof the body

Illustration 3.3

Indicators Arteries Veins CapillariesPeculiarity of the wallValvesPeculiarity of blood flowDirection of blood flow From arteries to veins

Table 3.1

Artificial pacemakerThe pacemaker has to function properly for theheart to beat rhythmically, otherwise the heart beatwill become non rhythmic. This can be lifethreatening if not resolved. However, nowadaysit is not a problem. Medical science has madepossible to implant the artificial pacemaker beneaththe skin through surgery. The artificial pacemakerhas two parts. The first part is the pulse generator.The second part is the mechanism which transmitselectric signals from the first part to the heart.Wilson Greatbatch, an American electricalengineer was the one behind the invention of thisequipment. Artificial pacemaker surgeries havebeen conducted since 1960.

Working of the heart

The heart beats continuouslywith a rhythm. Initiation of thecontraction and relaxation of theheart and regulation of the rateof heartbeat are controlled by theSino Atrial Node. It is located onthe right atrial wall. As itfunctions like an electric cell, itis known as pacemaker.

Complete illustration 3.3. Basedon the hints, analyse it andprepare notes on the function ofheart in the Science diary.

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Biology ̨ IX

Left ventricleDifferent partsof the body

Right ventricle Lungs

Hints• The carbon dioxide rich blood from different parts of the

body reaches the right atrium. The oxygen rich blood fromthe lungs reaches the left atrium through the pulmonaryveins. Subsequently atria contract.Where does the blood go when the atria contract?

• Further the ventricles contract.Does the blood flow back to the atria when the ventriclescontract? Why?When the ventricles contract, which blood vessels doesthe blood flow to?

• You know that blood supplies oxygen to all cells and receivescarbon dioxide from them. Reception of oxygen andexpulsion of carbon dioxide take place in the lungs.If so, what causes an increase in the level of carbon dioxidein the blood present in venacavae and the level of oxygenin the blood present in pulmonary veins?

Double Circulation

When blood flows from the heart to different parts of the bodyand vice versa, it passes twice through the chambers of the heart.Hence the circulation of blood in man is said to be doublecirculation. Double circulation includes systemic circulation andpulmonary circulation. Systemic circulation starts from the leftventricle and ends in the right atrium. The circulation which startsfrom the right ventricle and ends in the left atrium is calledpulmonary circulation. Complete the flowchart given below byincluding the heart chambers and the blood vessels involved indouble circulation.

Systemic circulation

Pulmonary circulation

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Biology ̨ IX

Illustration 3.4 Know your pulse

Identify the point on the wristwhere you can feel the pulse.

Capillaries in the liverCapillaries in the intestine Hepatic portal vein

LiverVenacava Hepatic veinHeart

Simple nutrients to the heartHow do the simple nutrients, which are absorbed into the bloodfrom the small intestine reach heart? Based on the indicators,analyse the description and flow chart given below and forminferences.

Portal Circulation

Certain veins do not reach the heart and they carry blood fromorgan to organ. Such veins are called portal veins. They beginfrom one organ as capillaries and end in another organ ascapillaries. Portal system is the system of blood circulation inwhich portal veins are included. Eg: Hepatic portal system.

Indicators

• Peculiarities of portal veins.

• The path of simple nutrients from the small intestine to theheart.

• Hepatic portal system.

Have you ever thought why simple nutrients reach the liver?Liver is the centre of metabolism. Simple nutrients undergoseveral changes in the liver. Storage of glucose in the form ofglycogen, releasing energy from fatty acids, producing cholesteroletc. are such changes. Have you understood the role of heart inthe distribution of simple nutrients to all parts of the body? It isthrough rhythmic heart beats that the functioning of heart ismade possible.

Heart beat, Pulse, Blood pressure

One systole and the subsequent diastole togetherconstitute a heart beat. It takes about 0.8 seconds.Contraction of the chambers of the heart is termed assystole. During this phase, blood flows from the atriato the ventricles and from the ventricles to outside.Subsequently along with the atria, the ventricles alsorelax. This stage of relaxation is termed as diastole. Inthis phase, chambers of the heart get filled with blood.

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Biology ̨ IX

Figure 3.6Digital B.P. apparatus

Figure 3.5Sphygmomanometer

The heart beats at an average rate of 72 times/minute.The wave - like movement formed due to the contractionand relaxation of the heart is felt throughout the wallsof the arteries. This is called pulse. Rate of pulse isequivalent to that of the heartbeat. Using the methodshown in illustration 3.4, check the number of pulses ina minute and record it. After doing exercise for a fewminutes check the pulse rate again. What difference doyou notice? What is its reason? Apart from the wrist,what are the other parts of the body where we can feelthe pulse?• both sides of the forehead.•

With the help of your teacher, check your own and yourclass mates’ pulse rate and record it. Compare the pulserate and the heart beat rate with the help of a stethoscope

and identify the relation between them.

About 70 ml of blood is pumped into the arteries everytime theheart contracts. The pressure exerted by this excess blood on thewalls of the arteries is systolic pressure. This is 120 mm Hg. Whenthe heart dilates fully the same quantity of blood enters the heart.A low pressure felt in the arteries during this time is known asdiastolic pressure. This is 80 mm Hg. The blood pressure of anindividual is stated in terms of these two pressures.Sphygmomanometer is the instrument (figure 3.5) used tomeasure blood pressure. Digital B.P. apparatus (figure 3.6) is alsoavailable nowadays. Visit a nearby laboratory or Health Centre.Seek the help of experts and get trained to measure blood pressureusing these two instruments.

Variation in Blood Pressure

You might have understood that the desired rate of blood pressureis 120/80 mmHg. The condition in which the blood pressureincreases above the normal rate is a disease condition calledhypertension. This happens due to many reasons. Unhealthyhabits, such as excess use of salt and fat, smoking, lack of excerciseetc. often lead to high blood pressure. The condition in which the

39

Biology ̨ IX

Capillaries Lymph duct

Blood

Lymph

Tissue fluid flows backto capillary

Cells

Intercellularspace

Tissuefluid

Glucose, O2Waste, CO2

Tissue fluid

Cell

Lymph capillary

ArteryVein

Blood

Tissue fluid to intercellularspace

Red blood cellCapillary

Illustration 3.5 Formation and backward flow of tissue fluid

blood pressure rate goes below the prescribed rate is calledhypotension. If not regulated, hypotension and hypertension maylead to stroke or heart attack.

From the blood to the cell

You have understood how blood reaches different parts of thebody. If so, how do cells get nutrients from blood?

Based on the indicators, analyse illustration 3.5 and thedescription given below and write your inference in the Sciencediary.

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Biology ̨ IX

Armoury of the human bodyAbout 4 inches of size, purple in colour, about 200gms weight. Located above the abdomen on the leftside of the stomach. The largest organ of the immunesystem, named spleen. Though it performs variousfunctions, providing immunity is the main function.Spleen consists of 2 types of tissues. Red pulp tissuesfilter and remove old and damaged RBCs present inblood. The reusable components in it, like iron areprotected. White pulp cells store T cells and B cellswhich are the main components of the immune system.The lymphocytes which identify and destroypathogenic bacteria and viruses that enter the body,are produced in the spleen and lymph nodes. In short,this small organ is considered as the armoury or militarycamp of the body.

Lymphducts

Spleen

Lymphnodes

Lymphducts

Figure 3.7Lymphatic system

The question raised by Sini in the beginning of the chapteris answered now. Along with blood, lymph alsoparticipates in the transport of materials. Observe the flowchart given below, prepare a description on how fatty acidand glycerol that are absorbed into the lymph from thesmall intestine reach cells and note it in the Science diary.

Fatty acid and glycerol Lacteals (Lymphs)

Small lymph ducts

Venacava (Blood) Heart

When blood flows through capillaries, the fluid part of bloodoozes into intercellular spaces through minute pores of thecapillary wall. This fluid, formed in the intercellular space, is thetissue fluid. It does not contain RBCs, large protein moleculesand platelets. Exchange of materials takes place between the tissue

fluid and cells. Tissue fluid isabsorbed into the blood andlymph capillaries. Lymph isthe tissue fluid inside thelymph capillaries.Indicators• Method of formation of

tissue fluid.• Exchange of materials

between cells and tissuefluid.

• Method of maintainingthe level of tissue fluidin intercellular space.

• Tissue fluid inside thelymph capillaries.

Large lymph ducts

You have understood that along with the bloodcirculatory system the circulation of lymph also takesplace. The lymph formed from blood passes through

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Biology ̨ IX

September 29World Heart Day

Deep from the Heart...

Exercise, alien to youth

walls lose elasticity and may rupture. Innerwall becomes rough. Hence RBCs mayclump together to form blood clot in thecoronary vessels which may cause heartattack.

Atherosclerosis is the condition in whichaccumulation of fat in the arterial walls takeplace due to consumption of excess fattyfood. As a result of this, the inner diameterof the artery reduces. Moreover arterial

Number of heart patients are booming Fat too a villain, if in excess

lymph ducts and returns toblood near the heart. In additionto lymph, the lymphatic systemconsists of lymph capillaries,lymph ducts, lymph nodes andspleen (figure 3.7). Spleen andlymph nodes play a major role indefending disease causinggerms.

A Healthy Heart –Vital for Life

A healthy heart is indispensablefor life. Excerpts from the wallmagazine prepared by studentson World Heart Day are shownbelow. Analyse them andprovide suggestions to maintaina healthy heart.

Heart transplantation and artificial heartOrgan donation and transplantation is not a breakingnews today. There are records of transplantation ofskin parts done in India during BC 200. In 1946 thefirst heart transplantation surgery was initiated bytransplanting a dog's heart by Demikov, a Russiandoctor. In humans, this surgery was first performedsuccessfully in 1967 under the leadership of ChristianBernard in South Africa. Eventhough the patientsurvived only for 18 days, it was a great beginning. In1994 Dr. P.Venugopal and team repeated the successat All India Institute of Medical Sciences, New Delhi.Heart transplantation is done world wide nowadays.Moving forward, in 1982 under the leadership of RobertJarvik and Johan Kolff another milestone was createdin the field of medical science by transplanting artificialheart in place of a diseased heart.

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Biology ̨ IX

How does waterreach the top of thistree through xylem?

Transportation in Plants

As in animals, substances are transported in plants too. You havestudied about the vascular tissues in plants. Complete table 3.2related to vascular tissues in plants and their functions.

Vascular Tissue Function

Xylem

Table 3.2 Vascular tissues in plants and their functions

Conduction through Xylem

Vascular tissues in plantsextend from the roots toleaves, in an interconnectedmanner. You know that thewater and salts that rootsabsorb from the soil reachthe leaves through xylem,the vascular tissue.

Transportation of watertakes place throughtracheids and vessels, thedead cells of xylem. Thediameter of vessels isgreater than that oftracheids. Vessels arearranged one above theother. As the cell wallsbetween the vesselsdisintegrate, they look likelong pipes (figure 3.8).

Did you notice Aby'sdoubt?

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Biology ̨ IX

Figure 3.9

Tracheid

Xylemvessel

Figure 3.8 Xylem

How does water reach the tree-topthrough the xylem naturally?

This happens due to the combinedaction of many processes. Let usexamine these processes.Transpiration, root pressure,cohesion and adhesion areimportant among them.

Transpiration can be observedthrough a simple experiment. Taketwo potted plants, one with leavesand the other without leaves.Cover them using transparentpolythene bags as shown in figure3.9.

Examine both the bags aftersometime.

What changes do you observe?

................................................................................

................................................................................

It can be inferred that water cameout from the leaves. Water isexpelled from leaves due toevaporation. This process is calledtranspiration.

What is the role of transpiration intransporting water absorbed by theroots to the leaves? Analyseillustration 3.6 and the descriptiongiven. Write a note in your Sciencediary on how water reaches leavesfrom roots.

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Biology ̨ IX

Water to cells byosmosis

Illustration 3.6Conduction of water in plants

Roothair

Root cells

Xylemvessel

Stomata

Water evaporatesthrough transpiration

Whi

le w

ater i

s los

t thro

ugh t

rans

pira

tion,

it ris

esth

roug

h the

xylem

. The

cohe

sion a

nd ad

hesio

nof

wat

er m

olec

ules

enab

le th

is ris

e.

Water content in soil

Water reaches leaf cells byosmosis.

Water molecules

Xylem vessel

Xylemvessel

Water is lost from the intercellular spaces of leaves throughstomata by transpiration. It reduces the pressure in the cells ofleaves. In order to compensate this pressure difference, waterenters these cells from adjacent cells through osmosis. Thetranspiration pull developed due to transpiration helps to carrywater to the top. Besides this, water molecules have the capacityto stick to themselves and with the walls of the vessels throughwhich they move. These processes are known as cohesion andadhesion respectively. Along with these, the root pressuredeveloped in the cells of root due to absorption of water also helpsin raising water.

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Biology ̨ IX

Sieve tube

Companioncell

Figure 3.10 Phloem

Transport through Phloem

Food is transported in the form ofsucrose through the sieve tube, themain part of the phloem. Like xylemvessels, sieve tubes are also seen aspipes arranged one above the other(figure 3.10). But differing fromxylem vessels, pores are seen in theircross walls. Through these pores,thecytoplasm of sieve tubes areinterconnected through which foodmolecules can travel. Companioncells are seen along with sieve tubes.They also help in the transportationof food.

Now, the difference between thetransport of substances in plants and human beings is clear toyou. Most of the vital activities taking place in plants and animalsare similar. One such activity is the production of energy. For theproduction of energy, is it enough that simple nutrients alonereach the cells? This question will be analysed in detail in thenext chapter.

1. Choose the simple nutrients which are absorbed into bloodfrom those given below.

A) Fatty acid

B) Amino acid

C) Fructose

D) Glycerol

E) Glucose

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Biology ̨ IX

Lungs

Heart

Body parts

Rightatrium

Leftatrium

Rightventricle

Leftventricle

A

B

2. Observe the illustration of the lungs, the heart and body parts.

Redraw the illustration and connect the lungs and body parts to the heartusing lines. Also show the route of blood flow.

3. Observe the figure showing the transportation ofmaterials in plants.

a. Identify the vascular tissues indicated by A andB.

b. Name the processes that help water absorbedby the roots to reach the leaves.

c. In some plants, the rate of transpiration is veryhigh. Does it affect the availability of water inthat locality? Why?

1. Construct a model of double circulation using coloured threads, thermocoletc. Show the direction of flow of blood also.

(Part where oxygenated blood is present – red colour

Part where deoxygenated blood is present – blue colour)

2. Prepare a Science edition by including information regarding Cardiac HealthCare.

Take a deepbreath.

Students practice breathing exercise as per the instructions of theteacher. Did you notice the message on the sticker? How does theavailability of energy increase when we breathe deeply? Can youmake an assumption? Note down the assumption in the Sciencediary. Let us examine whether your assumption is right.

Energy for doing work is released in the cells. Along with nutrients,oxygen is essential for this.

The respiratory system helps to take oxygen from the atmosphericair into the body.

List the parts of the respiratory system you know.$

$

$

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Biology ̨ IX

BronchioleThe terminal branches of bronchi thatopen to the alveoli. There are nocartilaginous rings in the bronchioles.

NostrilAn opening through which air passesin and out of the body.

BronchusBranches of trachea which enter thelungs, supported by cartilaginousbronchial rings.

Nasal cavityThe cavity which connects the nostrils withthe pharynx.

AlveoliDelicate air sacs,elastic in nature, seenat the tip of bronchioles. These air sacsare surrounded by a large number ofcapillaries. The exchange of gasestakes place here.

Trachea (Wind Pipe)A long tube strengthened by 'C' shapedcartilaginous rings. Cartilaginous ringshelp trachea to remain open always.

DiaphragmThe muscular wallthat separates thethoracic andabdominal cavities.

PleuraThe doublelayered protectivemembrane of thelungs. Pleural fluidseen in betweenthe membraneouslayers preventsfriction betweenlungs and walls ofthe thoracic cavity.

Illustration 4.1 Parts of the Respiratory System

Based on illustration 4.1 elaborate the list and prepare a table asgiven below.

Parts of the Respiratory System Peculiarity/Function

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Biology ̨ IX

Diaphragmcontracts

Ribs raise due to thecontraction ofintercostal muscles

Inspiration

Illustration 4.2 Respiratory movements

Volume of the thoracic cavityincreases. The pressure in thethoracic cavity becomeslower than the atmosphericpressure. Air enters in.

Ribs lower due tothe relaxation ofintercostal muscles

Diaphragmrelaxes

Expiration

Volume of the thoracic cavitydecreases. The pressure in thethoracic cavity becomesgreater than the atmosphericpressure. Air is expelled out.

Inspiration Expiration.......................... Diaphragm ..........................

.......................... Ribs ..........................

.......................... Volume of thoracic cavity ..........................

.......................... Pressure in the thoracic cavity ..........................

.......................... Air ..........................

Table 4.1 Thoracic movements and breathing

Respiratory tract is the pathway of atmospheric air from thenostrils to the alveoli. Analyse illustration 4.1 and complete thepathway of air.

Nostrils

Atmospheric Air into the LungsBreathing is a process that takes place without our knowledge,during which air is taken in and expelled.The basis of respiratory movements is the expansion andcontraction of the thoracic cavity. This repeats rhythmically. Withthe increase in size of the thoracic cavity, air enters the lungs.This is called inspiration. As a result of the contraction of thethoracic cavity, air is expelled from the lungs. This is calledexpiration. Let us now see how the thoracic cavity expands andcontracts rhythmically. The combined working of intercostalmuscles (specialised muscles between the ribs) and the diaphragm(dome-shaped muscular layer between the thoracic cavity andthe abdominal cavity) help in increasing and decreasing thevolume of the thoracic cavity. Complete table 4.1 by analysingthe description and illustration 4.2.

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Biology ̨ IX

Larger than the skin!

The surface area of the skin thatcovers the entire body is only twosquare metres. Whereas the surfacearea of both the lungs together turnup to be atleast 70 square metres.This is equivalent to the surface areaof a tennis court! This large surfacearea helps in the easy exchange ofrespiratory gases.

Exchange of Gases in the Alveoli

Atmospheric air reaches the alveoli asa result of inspiration. The exchange ofrespiratory gases like oxygen andcarbon dioxide takes place in thealveoli. How far is the structure ofalveoli suitable for this?

Based on the indicators, analyse figure4.1 and the description given andprepare notes in your Science diary.

Bronchioles, the terminal branches ofbronchi which enter the lungs end inmillions of alveoli. Alveoli increase the

respiratory surface area inlungs. They are surroundedby numerous bloodcapillaries. The inner wallof the alveoli is always keptmoist.The walls of thealveoli and capillaries aremade up of a single layer ofcells. In short, the surfacethat separates the blood inthe blood capillaries andthe air in the alveoli, hasthe thickness of two rows ofcells only.

During inspiration, theconcentration of oxygen is

higher and the concentration of carbon dioxide is lower in thealveoli. But, in the blood capillaries the concentration of oxygenis lower and the concentration of carbon dioxide is higher. As aresult of this, oxygen from the alveoli diffuses into the capillariesand carbon dioxide from the capillaries diffuses into the alveoli.

Oxygengoing in

CO2

O2

Red bloodcells

Wall of the alveolus

Capillarywall

Figure 4.1 An alveolus

Carbondioxide

going out

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Biology ̨ IX

Figure 4.2 Blood cells

Red blood cells

White blood cells

• Disc shaped• Between 45 lakh to 60 lakh

per milli litre.• Do not have nucleus or other

cell organelles.• Full of haemoglobin which has

affinity to oxygen

Proteinstrands

HaemIron

The structure of haemoglobin consists of fourprotein strands with iron containing haem.Oxygen combines with iron in the haem. Eachhaemoglobin molecule can carry four oxygenmolecules since a hemoglobin moleculecontains four protein strands and a haem.

Haemoglobin

Indicators

• Alveoli and the respiratory surface area.

• Peculiarities of the walls of the alveoli and blood capillaries.

• Concentration gradient of the respiratory gases and theexchange of gases.

In the previous lesson you learnt that simple nutrients aretransported through the plasma. Do you know which componentof blood carries oxygen? Haemoglobin in the red blood cells carryoxygen. Don’t you want to know the peculiarities of the red bloodcells?

Identify the difference in the number of red blood cells and whiteblood cells by observing a slide of blood through a microscope,with the help of your teacher. How far is the structure of red bloodcell suitable for carrying oxygen? Discuss and formulate yourinference.

Oxygen intoCells

How does oxygen reach the cellsfrom the alveoli? Analyseillustration 4.3 and complete theflow chart given below using theindicators.

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Biology ̨ IX

Oxyhaemoglobin

Alveolus

Oxygen

Haemoglobin

Bloodcapillary

Diffusion ofoxygen into thecells through thetissue fluid

Cells in tissues

Oxyhaemoglobin Haemoglobinreleases oxygenand becomesfree

Illustration 4.3 Diffusion of oxygen

Tissue fluid

When trapped in asmoke - filled room

Haemoglobin has more affinity to carbonmonoxide than oxygen. Haemoglobincombines fast with carbon monoxideand forms a more stable compoundcalled carboxy haemoglobin. Unlikeoxyhaemoglobin, carboxy haemoglobindoes not breakdown and causes thedestruction of the haemoglobin molecule.This may become dangerous in somesituations. If trapped in rooms where thereis fire, it leads to inhaling of carbonmonoxide along with smoke. So the rescueof persons from a smoke filled room isequally important to extinguishing of fire.Cover your nose and mouth with a dampcloth and move to an aerated place bysprawling on the ground. By this way,rescue operators can also rescue personswho cannot escape themselves.

Hints

• Tissue fluid• Blood• Oxyhaemoglobin• Cell• Oxygen

Haven’t you understood the role ofhaemoglobin in the transport ofoxygen? The main constituent forthe synthesis of haemoglobin is ironmolecules. So it is said that fooditems like leafy vegetables with ironcontent should be included in ourdiet. The average amount ofhaemoglobin in a healthy man is15gm/100ml and that of woman is13gm/100ml of blood. Anaemia isa condition in which the amount ofhaemoglobin in the blood decreases.You have now understood theimportance of distribution of irontablets in schools as a part of theWIFS project.

Oxygen in thealveoli

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Biology ̨ IX

GlycolysisThe first phase in cellular respiration. Glucose isconverted to pyruvic acid. 2 ATP molecules areproduced. This process occurs in the cytoplasm.It does not require oxygen.

Krebs CycleThe second phase in cellular respiration is that whichoccurs in the mitochondria. Through a series ofchemical changes pyruvic acid is converted tocarbon dioxide and water. 28 ATP molecules areproduced. It requires oxygen.

Illustration 4.4 Cellular respiration- stages

Mitochondria

................ + ................ Cellular respiration ................ + ................ + 30 ATP

Indicators Glycolysis Krebs Cycle

Part where cellularrespiration takes place

Need of oxygen

Number of ATP moleculesproduced

ProductsTable 4.2 Cellular respiration

You have understood how energy is released from glucose.Complete the worksheet of cellular respiration based on theindicators given below.

To release energyHow does oxygen that reaches cells help in releasing energy? Youknow that energy is released mainly from glucose. The process bywhich energy is released from glucose in cells is called cellularrespiration. Cellular respiration occurs in two steps. Analyseillustration 4.4 and complete table 4.2 given below.

Haven't you understood the chemistry of respiration? Analysethe process of cellular respiration and find the relation betweenrespiration and photosynthesis and complete table 4.3.

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Biology ̨ IX

7%Dissolved in

plasma water

23%As carbaminohaemoglobin,

formed bycombining with

haemoglobin

70%As bicarbonates,formed by gettingdissolved in waterin the RBC

CO2

CO2

CO2

CO2

CO2

Alveolus

Tissue fluid

Bloodcapillary

Illustration 4.5 Expulsion of carbon dioxide

CO2 CO2CO2

Inside the lungs carbaminohaemoglobin andbicarbonate breakdown andcarbon dioxide is released.

C O 2C O 2 C O 2

Indicators

• Role of tissue fluids.

• Transportation of carbon dioxide and the components ofblood.

• Expulsion of carbon dioxide from the lungs.

Indicators Photosynthesis Respiration

Functions

Phases of the reaction

Substrates

Products

Table 4.3 Respiration and photosynthesis

Expulsion of Carbon dioxide

Carbon dioxide and water are formed in the cells as a result ofrespiration. During respiration, trace amount of water iseliminated from the body in the form of water vapour. But how iscarbon dioxide, the major byproduct of respiration, eliminatedfrom the cells? Based on the indicators, analyse illustration 4.5given below and note down your inferences in the Science diary.

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Biology ̨ IX

Bacteria

Yeast

Illustration 4.6Anaerobicrespiration

In the cytoplasm ofbacteria and yeast

When carbon dioxide becomes excessive

You have understood that carbon dioxide is expelled through thelungs. What will happen if this does not take place? Analyse thedescription given below on the basis of indicators and write itdown in the Science diary.

Various metabolic activities take place in our body. The cellularrespiration is one of its kind. As a result of cellular respirationproducts like carbon dioxide, water, etc., are formed. When thelevel of these products increases beyond the limit, the veryexistence of life is in danger. Carbon dioxide combines with waterpresent in and out of the cell to form carbonic acid. The increasein the level of carbonic acid increases the acidity in the body. Thischanges the internal environment. Substances that cause changein the internal environment must be duly removed. This is also apart of maintaining the homeostasis.

Indicators

• Change in homeostasis due to the increase in carbon dioxide.

• Respiratory system and the maintenance of homeostasis.

Respiration without oxygen!

Many organisms like bacteria, yeast, etc., can survive even in theabsence of oxygen. If so, how do they get energy for their lifeprocesses? Based on the indicators given, analyse illustrations 4.6and 4.7 and write your inferences in the Science diary.

Glucose

2 ATP

Pyruvic acid

Lactic acid Alcohol + CO2

Lactic acid fermentation Alcohol fermentation

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Biology ̨ IX

Fermentation in Daily Life

Indicators

• Fermentation during the curding of milk and themicroorganisms.

• Process behind batter becoming soft and puffy.

• A practical definition for fermentation.

In certain circumstances, anaerobic respiration takes place inhuman beings also. During strenuous exercise, energy utilizationin muscles increase and the oxygen availability decreases. In suchsituations, muscle cells produce energy by anaerobic respirationand lactic acid is formed in the muscle cells.

Fermentation is used not only in daily life, but as a technology in theindustrial sector also. Production of many bakery items can beassociated with this. The possibilities of this technology can be madeuse of in small scale industries and in other vocations. Conduct aworkshop on the topic with the help of experts.

Do not damage the respiratory system

What are the instances that are harmful to the health of therespiratory system?

••

Yeast

Anaerobicrespiration

Illustration 4.7 Fermentation

Alcohol, CO2

Fermenting batter (a mixture offlour and liquid) to soften it.

Lactic acidCurding milk

Lactobacillusbacteria

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Biology ̨ IX

Normal alveoli

Illustration 4.8 Ill- effects of smoking

Lung CancerCarcinogens present in tobacco cause lungcancer.

Normal lungs Lungs affected bycancer

EmphysemaAlveoli rupture due to the lossof elasticity, by the deposition oftoxic substances contained intobacco. This reduces therespiratory surface and reducesvital capacity.

Alveoliaffected byemphysema

BronchitisThe tar, carbon monoxide, etc.,in tobacco leads to thedeposition of mucus and theswelling of lungs due to theproliferation of germs in thealveoli.

Normalbronchioles

Affectedbronchioles

Lungs can be damaged by dust, germs, chemicals, etc., which arecontained in the air we breathe in. The respiratory system itselfhas certain mechanisms to protect lungs from these hazardousinstances.

Smoking is a bad habit that harmfully affects the human race.What are the respiratory disorders caused by smoking? Conducta seminar in your class on the effects of smoking by analysingillustration 4.8 and collecting additional information.

Besides protecting the lungs from diseases, we must also beequipped to face unexpected accidents. There may be situationsthat lead to drowning. As we can’t breathe air in water, it isimpossible to remain in water for a longer time. There is a very

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Biology ̨ IX

Figure 4.3 Measurement of vital capacity

low chance of self rescue too. Hence the person who meets withthe accident must be rescued from water and first aid must beprovided. Hence it is necessary that all of us must know how toexpel water which has entered the body and how to perform theartificial respiration. Observe the video in Samagra and practicewith the help of your teacher.

Vital Capacity

Apart from protecting the lungs, care should be taken to increaseits capacity too.

Tidal volume is the volume of air we breathe in and out duringnormal breathing. In humans, the tidal volume is about 500 ml.Vital capacity is the volume of air that can be breathed out byforceful expiration after maximum or forceful inspiration. Vitalcapacity can be taken as an indicator of normal and healthyrespiratory activity and the strength of muscles in the thoraciccavity. This is about 4.5 litres in male and about 3 litres in female.

Let's measure vital capacity

Arrange the plastic jars andtubes as shown in figure 4.3.After a forceful inspiration,blow air forcefully into the firstjar holding the funnel aroundthe mouth. Measure the amountof water that falls into thesecond jar. The volume of waterwill be proportional to the vitalcapacity. Compare the vitalcapacity of friends in yourclassroom. Vital capacity can beincreased through breathingexercise.

Doesn't the level of oxygen dissolving in blood increase whenvital capacity increases? And yes, due to this, energy productionalso increases!

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Biology ̨ IX

Exchange of Gases

Directly between tissues

Table 4.4

OrganismRespiratory Organ/Mode of Respiration

Amoeba

Cockroach

Fish

Have you understood the meaning of the message given at thebeginning of the chapter. Modify the guess you have recorded, ifnecessary.

Respiration in other Organisms

You know that other organisms too respire like humans. Cellularrespiration is a process more or less similar in all organisms.Thestructure of the respiratory organs and the process of exchangeof gases become complex from organisms with simple organisationto complex organisation.

Don't you remember the process of respiration in organisms likeamoeba, fish, insects, etc. that you have studied in your lowerclasses? Collect data on respiratory diversity in organisms andcomplete table 4.4.

Do plants breathe?

Do plants respire like animals? Discuss this on the basis ofindicators and draw inferences about respiration in plants.

Even though plants need less energy when compared to animalsthey also utilize glucose for the production of energy. The oxygenneeded for the oxidation of glucose is also absorbed fromatmospheric air. Plants have different mechanisms for theexchange of gases. You already know about the stomata seen onleaves and green tender stems. These are the centres of exchangeof gases in plants.

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Biology ̨ IX

Figure 4.4 Lenticel

OxygenCarbon dioxide

Exchange of Gases

How do the roots and stems get oxygen? Observe the stem ofMexican lilac (Sheemakonna) and moringa and the root of jackfruittree using a hand lens.

Can't you see small pores on the surface of stems and roots?These are called lenticels. Exchange of carbon dioxide andoxygen takes place in stems and roots through the cells oflenticels by diffusion.

Oxygen is inevitable for the existence of all organisms. Weknow that plants play a very important role in producingsufficient oxygen in nature. But uncontrolled humaninterference in nature has increased the rate of pollutiontremendously. Atmospheric pollution adversely affects theexistence of life on earth. It is the duty of every human beingto conserve and preserve nature with utmost care for theexistence of life, in the years to come.

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Biology ̨ IX

1. Reason for the diffusion of oxygen from alveoli to blood.

A. Low concentration of oxygen in blood.

B. As the walls of the alveoli and blood vessels are thin.

C. High concentration of oxygen in alveoli.

D. All the above.

2. Observe the two reactions given below.

Reaction 1) C6H12O6 + 6O2 6CO2 + 6H2O + Energy

Reaction 2) 6CO2 + 6H2OLight C6H12O6 + 6O2Chlorophyll

a) Identify the process occurring in plants and in animals.

b) Which is the process that takes place only in plants?

3. Explain the role played by haemoglobin in thetransportation of oxygen and carbon dioxide.

1. 'Smoking is suicide and murder at the same time'. Preparea poster for the Health Club of your school based on theabove statement.

2. Interview a medical practitioner by preparing aquestionnaire on the topic 'Increasing Lung Diseases'.

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Biology ̨ IX

Notes

CONSTITUTION OF INDIAPart IV A

FUNDAMENTFUNDAMENTFUNDAMENTFUNDAMENTFUNDAMENTAL DUTIES OF CITIZENSAL DUTIES OF CITIZENSAL DUTIES OF CITIZENSAL DUTIES OF CITIZENSAL DUTIES OF CITIZENS

ARTICLE 51 A

Fundamental Duties- It shall be the duty of every citizen of India:

(a) to abide by the Constitution and respect its ideals and institutions,the National Flag and the National Anthem;

(b) to cherish and follow the noble ideals which inspired our national strugglefor freedom;

(c) to uphold and protect the sovereignty, unity and integrity of India;

(d) to defend the country and render national service when called upon to do so;

(e) to promote harmony and the spirit of common brotherhood amongst allthe people of India transcending religious, linguistic and regional orsectional diversities; to renounce practices derogatory to the dignity ofwomen;

(f) to value and preserve the rich heritage of our composite culture;

(g) to protect and improve the natural environment including forests, lakes,rivers, wild life and to have compassion for living creatures;

(h) to develop the scientific temper, humanism and the spirit of inquiry andreform;

(i) to safeguard public property and to abjure violence;

(j) to strive towards excellence in all spheres of individual and collectiveactivity so that the nation constantly rises to higher levels of endeavourand achievements;

(k) who is a parent or guardian to provide opportunities for education to hischild or, as the case may be, ward between age of six and fourteen years.

Forests have a great role in conserving the health of the environment in which we live.Forests are decisive in many respects. Source of the water we drink and the air we breathe,balancing atmospheric temperature, determining weather, managing agriculture, source ofour food etc., are some of those areas.

Wild animals inhabit forests. Each animal has a function to perform in the environment inwhich it lives. Thus wild animals have a vital role in aspects like pollination of plants,dispersal of seeds, sustenance of forests etc.

It is our duty to protect and preserve forests, lakes, rivers, wild animals etc,which are allpart of our nature. Also, Article 51(g) of our constitution reminds every citizen of India tohave a compassion for living creatures.

Activities taken up for the conservation of forests and wild life by the Forest Department:

• Establishing Forestry clubs in schools, for spreading knowledge about forests.

• Establishing Eco-tourism centres as a part of encouraging eco-friendly tourism.

• Conducting Nature study camps as a part of forest and wild life education.

• Making public places green.

• Providing financial aid to conserve 'kaavu'.

• Turtle conservation project.

• Instituting 'Vanamitra award' for promoting creative contributions in the field of greenprojects.

• Instituting 'Prakritimitra award' for conserving habitats outside forests and biodiversity.

• Conducting the 'Citizen Conservator Programme' for ensuring the role of public in forestconservation.

Toll free number of Forest department: 18004254733

Its high time we protected nature and natural resources….!

The National Anthem - Education Observer

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