G.C.E.(A.L.) Support seminar - 2014 Biology - Paper I Answer Guide

QuestionNumber

Answer QuestionNumber

Answer

(1) 5 (26) 2

(2) 1 (27) 2

(3) 2 (28) 2

(4) 4 (29) 3

(5) 5 (30) 3

(6) 5 (31) 2

(7) 3 (32) 5

(8) 4 (33) 5

(9) 4 (34) 4

(10) 2 (35) 4

(11) 5 (36) 3

(12) 4 (37) 2

(13) 5 (38) 2

(14) 5 (39) 3

(15) 5 (40) 2

(16) 3 (41) 4

(17) 5 (42) 3

(18) 2 (43) 3

(19) 3 (44) 4

(20) 1 (45) 2

(21) 4 (46) 1

(22) 5 (47) 1

(23) 4 (48) 1

(24) 3 (49) 5

(25) 4 (50) 2

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Biology - Paper II Answer Guide

Part A – Structured Essay

1. (A)(i) Mention the type of monomer/ unit molecule of following organic compounds. (a) Cellulose - • Glucose (a) Pectin - • Galactouronic acid (c) Inuline - • Fructose (d) Glycogen - • Glucose (4 × 2 marks)

(ii) Out of the above compounds, a - d mention two types of structural and storage compounds.

Structural - • Cellulose • Pectin

Storage - • Inuline • Glycogen (4 × 2 marks)

(iii) Draw the common structural formula of the monomer molecule of proteins.

C

R

H

COOHNH2

(1 × 2 marks)

(iv) Name a simple experiment suitable to identify proteins in the laboratary and write the steps of it in order. • Birurette test • Take 2ml of protein solution/ suspension to a test tube and add equal volume of 5% KOH/ NaOH and • few drops of 1% CuSO4 solution. • If a purple colour is given it resembles the presence of proteins. (4 × 2 marks)

(v)(a) Mention the three structural components of the cytoskeleton. • Microtubules • Microfilaments/ actin filaments. • intermediate filaments. (3× 2 marks)

(b) Mention three functions of the cytoskeleton. • Provide the mechanical strength to cytoplasm • Suspend organelles (at proper locations). / Support organelles • Movement of cytoplasm/ cytoplasmic streaming • Movement of organelles/ chromosomes when necessary. • Give a shape to the cell. Any 3 (3× 2 marks)

(c) Write two functions of the cytoskeleton in the cell division of an animal cell. • Formation of mitotic spindle (by microtubules) • Formation of cleavage Furrow (by microfilaments) (2× 2 marks)

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• Following is a diagram of a tissue located in human body. ^B) Questions (i) to (iv) are based on it.

a c

b

(i) Identify the tissue shown in the above in the above diagram. • Areolar tissue/ loose connective tissue (1 × 2 marks)

(ii) Label a, b and c structures.

a Collagen fibres/ white fibres

b Elastin fibres / yellow fibres

c Matrix (3 × 2 marks)

(iii) Mention one location of identified tissue in B(i) in the human body. • In the mucosa of the digestive tract./ sub mucosa of the digestive tract/ dermis of the skin/ (1 × 2 marks)

(iv) Name three cell types present in above tissue identified in B(i) and mention one main function of each. Cell type Main function

• Mast cells secretion of heparin/histamine • Fibrocytes secretion of fibres /matrix • Macrophages Phagocytosis • Fat cells storing fat • Paranchymal cells differentiating into other cells Any (3 + 3) (6 × 2 marks)

(v) State three structural features found in a meristematic cell of plants. • Isodiametric shape • Presence of thin primary cell walls • Presence of a large nucleus • Presence of a thick cytoplasm • Undifferentiated cells • Absence of vacuoles /filled with cytoplasm Any 3 (3 × 2 marks)

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(vi) Name permanent tissues which consist of lignified cells found in plant bodies. • Sclerenchyma • Xylem • Phloem (3 × 2 marks)

(C) (i) What is meant by metabolism? • The sum of overall chemical processes take place in living organisms. (1 × 2 marks)

• Following is a diagram of a metabolic process which takes place in a particular plant. Questions (ii) to (v) are based on the following diagram.

x

y

b (4C)

d (4C)

d (4C)

2 PGA(3C)

2PGAL

NADPH

NADPH

ADP

ATP

f

a + CO2

e + CO2

Q

R

NADP +

NADP +

(ii) Name the above metabolic process and one plant in which the above process takes place. Process - C4 photosynthesis/ the dark reaction of C4 photosynthesis Plant - Saccharum/ Zea mays (2 × 2 marks)

(iii) Label a, b, d, e , f, compounds and x and y enzymes.

a Phospo Enol pyruvate ( PEP) b Oxalo Acetate (OAA) d Malate e Pyruvate f RUBP x PEP Carboxylase y RUBP Carboxylase (7 × 2 marks)

(iv) Name cells labeled as Q and R. Q - leaf mesophyll cells R - Bundle sheath cells (2 × 2 marks) (50 × 2 = 100 marks)

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2.(A)(i) (a) What is meant by classification of organisms? • Grouping of organisms regarding common characteristics. (1 × 2 marks)

(b) Mention the main difference between artificial and natural classifications. • The evolutionary relationships of organisms are taken into consideration in natural classification but not considered in artificial classification. (1 × 2 marks) (c) Mention three criteria on which the present classification system is based. • The DNA base sequence of important genes • mitrochondrial DNA • Base sequence of rRNA • The amino acid sequence in common proteins • The molecular structure of cellular components. Any 3 (3 × 2 marks)

(ii) Name the domain into which the following genera of organisms belong, according to the present classification system. (a) Marchantia - Eukarya

(b) Methanobactetium - Archea (2 × 2 marks)

(iii) This question is based on following groups of organisms. ÷ Insecta ÷ Cestoda ÷ Mammalia ÷ Monocotyledonae ÷ Dicotyledonae ÷ Crustacea ÷ Chondrichthyes ÷ Pterophyta Select the group of organism which consists of following characteristics from the above list and mention it in front of the relevant characteristic' (a) Presence of tegument with microvilli - Cestoda (b) Consists of green glands and two pairs of Antennae - Crustacea (c) Ventral heart and single circulation - Chondrichthyes (d) Skin with sebaceous glands - Mammalia (e) Presence of open vascular bundle - Dicotyledonae (f) Presence of Trimerous flowers with periyanth - Monocotyledonae (g) Presence of circulatory systems without respiratory pigments - Insecta (h) Presence of monoecious gametophyte - Pterophyta (8 × 2 marks)

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(B) This question is based on following diagrams.

A C B E D

(i) Select the organism which possess following features and mention the symbol and Phylum of each in given table.

FeatureSymbol of

organismPhylum

(a) Possess cnidocytes C Coelenterata

(b) Possess water vascular system D Echinodermata

(c) Possess the radula A Mollusca

(d) Possess Chitinous exoskeleton E Arthropoda

(e) Possess flame cells B Ptatyhelminthes

(10 × 2 marks)

(ii) Out of above mentioned animal Phyla in B (i); (a) In which phylums specific respiratory structures are absent? .• Coelenterata • Platyhelminthes (2 × 2 marks)

(b) In which phylums excretory systems are absent? • Coelenterata • Echinodermata (2 × 2 marks)

(c) Mention phylums consist of open circulatory systems. • Mollusca • Arthropoda (2 × 2 marks)

(C)(i) Mention one invertebrate Phylum each which consists of following types of skeletons.

(a) Hydrostatic skeleton - Annelida/ Nematoda (b) Endoskeleton - Echinodermata/ Mollusca (2 × 2 marks)

26' Wiia Ydlj, jr®Ol m%pdrl jHqy lSmhla my; olajd we;'

(a) ffrfidauh (b) fldauh

(c) n,aì,h (d) iAlkaO wdlkaOh

fuu jHqy w;=˙ka" Y,al m;% yd iqma; wxl=r ±lsh yelafla ljrl o@

(1) a j, muKls' (2) a yd b j, h'

(3) a, b yd c j, h' (4) a, b yd d j, h'

(5) a, b yd e j, h'

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÷ Following is a picture of the human upper limb and associated structures as shown in the following figure. Questions (ii) to (vi) are based on it.

(ii) Label a – e structures in the figure.

a - clavicle

b - scapula

c - humerous

d - ulna

e - radius' (5 × 2 marks)

(iii) Which joint of human upper limb is important in making movements over a wide range. • shoulder joint (1 × 2 marks)

(iv) Mention two types of specific grips of human hand. • precision grip • power grip (2 × 2 marks)

a

b

c

d

e

(v) State the type of above mentioned grips used in the following occasions. (a) sewing by needle - precision grip (b) tug of war - power grip (2 × 2 marks)

(vi) Mention three adaptations of human upper limb to lift weights. • strong humerous • attachment of strong muscles on the articulatory surface of bones • ability to make lever movements • ability of hand to pronate and supinate • broad hand • grasping ability of hand Any 3 (3 × 2 marks)

(vii) Name the bones directly participate to form following joints.

(a) Wrist Joint • radius • proximal carpals

(b) Ankle joint • tibia • Fibula • Talus (5 × 2 marks) (51 × 2 = 102 marks) (Max 100)

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3.(A)(i) (a) What is a stomata? • The epidermal structure containing a pore surrounded by two guard cells which get involves in gas exchange of leaves. (1 × 2 marks)

(b) State two ways that the cells associated with stomata differ from normal epidermal cells. • presence of chloroplasts • unevenly thickened walls/ presence of radial thickening • shape Any 2 (2 × 2 marks) (c) Name two sites of transpiration in plant body other than stomata? • Lenticell • Cuticle (2 × 2 marks) (ii) (a) Write two advantages of transpiration to the plant. • Cooling of plant body • Transportation of minerals • vertical transportation/ upward transportation of water • absorption of water Any 2 (2 × 2 marks)

(b) Write four adaptations of plants to minimize transpiration. • Reduction of leaves/ small leaves/ leaves becoming thorns • Epidermal hairs • Sunken stomata • Thick cuticle / presence of shiny cuticle • rolling of leaves in dry season • falling of leaves in dry season Any 4 (4 × 2 marks) (c) Name two internal factors that affect transpiration.

• Number of stomata/ density of stomata • Internal structure of leaf • amount of water in plant body Any 2 (2 × 2 marks)

(iii) What is guttation? • exit of water in liquid state through • hydathodes of the leaves of some plants during night (2 × 2 marks)

(iv) Mention two distinguishable features of guttation over transpiration. • exit of water in liquid state • exit of minerals with water • occurrence though hydathodes • takes place only in night • doesn't take place in all terrestrial plants. Any 2 (2 × 2 marks)

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(v) (a) What is the assumption used when carrying out an experiment to investigate the rate of transpiration of a plant twig using the photometer? • An equal volume of water absorbed from the apparatus get expelled from the twig by transpiration. (1 × 2 marks)

(b) What is the error of that assumption? • The volume of water absorbed by twig is not expelled by water by transpiration. • due to use in metabolism of the twig (2 × 2 marks)

(B) (i) Mention one suitable example to demonstrate that the phloem translocation takes place under hydrostatic pressure. • Obtaining sweet toddy by tapping coconut/ when obtaining latex from rubber. (1 × 2 marks)

(ii) Define 'source' and 'sink' regarding phloem translocation. (a) source ( The initial site of the tissue in phloem translocation. (b) sink ( The destination of the tissue in phloem translocation. (2 × 2 marks) (iii)(a) What is meant by 'phloem loading'? • Secretion of sucrose actively by transfer cells. • From leaf mesophyll cells to seive tube elements. (2 × 2 marks)

(b) Sucrose is the main form of organic food translocated in plant. Mention two advantages of using sucrose in translocation. • It is highly soluble in water. • It is a metabolically inactive substance.

(2 × 2 marks)

(iv) (a) State two importants of Phloem translocation. • To transport organic foods within plant/ To transport sucrose from production site to storage/ consuming site chemical substances. • To Transport amino acids / vitamins / growth substances / K+ / Phosphate / applied chemical substances through the plant body. (2 × 2 marks)

(b) What are the principles on which transportation of water across membranes is based? • Diffusion • Osmosis • Mass flow • imbibition (4 × 2 marks)

(v) What are the underlying principles of upward movement of water and minerals in plants? • The water potential gradient (from soil to atmosphere) • Adhesive forces of water. • Cohesive forces of water. • Transpiration pull. (4 × 2 marks)

(C) (i) Write the tissue layers of a dicot primary root from outer to inner in order. • epidermis, cortex, endodermis, pericyle, primary phloem, primary xylem. (6 × 1 marks) (Give marks only for the answers given in order.)

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(ii) Name the meristematic tissues contribute in the secondary growth of a dicot root and mention the secondary tissue type derive from each.

meristematic tissues secondary tissues • Vascular cambium – • Secondary phloem • Secondary xylem • Cork cambium – • Secondary cortex • cork (6 × 2 marks)

(iii) Name the tissue types of dicot stem and dicot root from which lateral branches and lateral roots arise.

(a) lateral branches of stem - epideramis

(b) lateral roots - pericycle (2 × 2 marks)

(iv) Mention two functions of the bark of dicot stem. • protection • translocation of organic food • gas exchange Any 2 (2 × 2 marks) (50 × 2 = 100 marks) 4.(A) (i) What is meant by microorganisms? • Organisms which are smaller than 0.1mm hence not seen with naked eyes (1 × 2 marks)

(ii) Microorganisms possess different types of modes of nutrition. mention the carbon and energy sources of microorganisms possess following modes of nutrition.

mode of nutrition energy sources carbon sources

(a) chemoautotrophic

(b) Photoheterotrophic

• Inorganic chemicals

• light

• CO2 / inorganic Carbon

• Organic carbon

(4 × 2 marks) (iii) Name four physiological groups of microorganisms related to oxygen and mention one generic name as an example for each group.

group genera

• acrobic microoraganisms

• Obcigatory anerobic microoraganisms

• Facultative anaerobic microoraganisms

• Microaerophilic microoraganisms

• Acetobacter

• Clostridium

• Saccharomyces

• Lactobacillus

(8 × 2 marks)

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(iv) Mention three morphological forms found among bacteria. • Coccus, bacillus, spiral (If all three are written correctly) (1 × 2 marks)

(B) (i) What is meant by 'food spoilage' ? • Becoming of food unfit for consumption due to growth of microorganisms in it which causes to alternations of physical chemical and biological structures. (1 × 2 marks)

(ii) Name the major chemical changes take place in food spoilage and mention two end products of each type.

chemical change products given in chemical change

(a) Putrefaction

(b) Fermentation

(c) Rancidity

• amino acids • ammonia • amines • H

2O (Any 2)

• acids • alcohols• gases (Any 2)

• Fatty acids • Glycerol

(9 × 2 marks)

(iii) State four physical changes that take place in food spoilage. • Softening • Pigmentation • ropiness • Slime or gum formation • toxin accumulation Any 4 (4 × 2 marks)

(iv) What are the internal factors affect the food spoilage? • The pH value of food • Biological structure of food. • Nutrient content • Moisture content (4 × 2 marks)

(v) (a) Why food preservation should be done? • Food are readily decomposed by microbes (spoiled) • When food production exceeds the demand should be preserved. (2 × 2 marks)

(b) Write three main principles on which the food preservation methods are based. • prevention of entry of microorganism into food • prevention of growth of microorganism into food • removal or destroying of microbes in food (3 × 2 marks)

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(C) (i) Name three food borne infective diseases and the causative microbe for each.

Infectious diseases causative microbes

÷ Typhoid fever

÷ Dysentery

÷ Cholera

÷ Salmonella typhi

÷ Shigella

÷ Vibrio cholerae

(6 × 2 marks) (ii) Define following terms regarding microbicidal agents. (a) Disinfectants

÷ Chemicals used to destroy or reduce microbial populations in inanimate environment. (1 × 2 marks)

(b) Antiseptics

÷ Chemicals used to reduce microbial populations on the skin. (1 × 2 marks) (c) Antibiotics

÷ Chemical compounds naturally produced by microorganisms which are inhibitory to other micro organisms. (1 × 2 marks)

(iii) Name one antibiotic which inhibit the synthesis of fungal cell membranes.

÷ Ketoconazole/ Clotrimazole (1 × 2 marks)

(iv) Mention one species of micro organisms which synthesizes following antibiotics.

antibiotic species

÷ Penicillin

÷ Streptomycin

÷ Tetracycline

÷ Penicillum notatum/ Penicillum chrysogenum

÷ Streptomyces griseus

÷ Streptomyces aureofaciens

(3 × 2 marks) (50 × 2 = 100 marks)

* *

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Part B - Essay

5. (a) Name the three main steps when a glucose molecule undergoes aerobic respiration. 1. Glycolysis 2. Kreb’s cycle/ TCA cycle/ Citric acid cycle 3. Electron transporative chain

(b) Briefly explain the process of aerobic respiration of a glucose molecule, take place in a mitochondria. 4. When O2 is present, 5. the products of Glycolysis, 6. Pyruvate molecules (C3 compound) 7. enter the matrix of mitochondria and 8. It joins with co-enzyme A and produce Acetyl - Co-A. 9. Co2 molecule/ 2 Co2 per two pyruvate get released. 10. NADH/ 2 NADH per 1 pyruvate are produced in this step, 11. Kreb's cycle 12. happens in the matrix of mitochondria 13. Acetyl - Co - A reacts with Oxalo Acetic Acid and 14. Citric acid/ Citrate is produced 15. Citric acid undergoes a series of decarboxylative 16. and oxidative reactions and 17. regenerates Oxalo Acetate 18. All of these reactions are catalysed by specific enzymes 19. at the end of Kreb’s cycle, 1 ATP is produced from 1 Pyruvate/ 2 ATP are produced from 1 glucose molecule. 20. 4 NADH/ 8 NADH per 1 glucose molecule. 21. 1 FADH2 / 2 FADH2 per 1 glucose molecule are produced. 22. In electron transport chain 23. In glycolysis and Kreb's cycle (in mitochondria) 24. reduced co-enzymes, NADH and FADH2 25. are guided to electron transport chain take place at cristae/ inner membrane of mitochondria. 26. To convert energy in them into ATP. 27. H+ in NADH and FADH2 (in reduced co-enzymes) transmit through 28. a series of electron carriers 29. and finally, reacts with O2 and water is produced. 30. Cytochrome Oxidase enzyme catalyses this step 31. ATP is produced using energy released in electron transport chain. 32. By oxidative phosporylation. 33. from 1 NADH molecule 3 ATP are produced 34. from 1 FADH2 molecule 2 ATP are produced. 35. 10 NADH have been produced in former steps (2 in glycolysis/ cytoplasma matrix, 8 in mitochondria) 36. and 2 FADH2 37. The total number of ATP produced in electron transport chain is 34 (per one glucose) 38. Therefore, the total numbering of ATP produced with in mitochondria is 36 (per one glucose) (38 × 4 = 152) (max 150)

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6. (a) Describe the gross structure of human heart. 1. Cone shaped, muscular hollow organ 2. Surrounded by pericardium 3. Wall consists of 3 layers 4. Outer epicardium 5. Middle myocardium/ Cardiac muscle 6. Inner endocardium 7. Consists of 4 chambers 8. Two auricles and two ventricles 9. a longitudinal septa divides the heart into two halves 10. As left and right halves 11. each half consists of an auricle and ventricle 12. Tricuspid valve is located between right auricle and right ventricle 13. Bicuspid valve is located between left auricle and left ventricle 14. Papillary muscles are attached on to ventriculer walls 15. Chordae tendinae join the Papillary muscles with cusps of valves 16. Pulmonary artery arises from right ventricle 17. Semilunar valves are located at the opening of Pulmonary valve 18. The aorta arises from left ventricle 19. Semilunar valves are located closer to the opening of aorta. 20. Four Pulmonary veins open to the left auricle 22. ventriculer walls are thicker than auricular walls 23. Walls of left auricle is much thicker than that of right auricle

(b) Mention the structures related with the myogenic stimulation of human heart and location of each and briefly describe the sequential process of myogenic stimulation. 24. Sino-Auricular node 25. located in the right auricular wall closer to the opening of superior vena cava 26. It consists of mass of neuromuscular cells. 27. Auricular – Venrticular node. 28. located on the inter auricular septum 29. At the inferior region of the right auricle. 30. Auricular – Venrticular bundle/ bundle of HIS 31. initiates from AV node and run down 32. Get divided into two branches at the upper level of inter ventricular septum. 33. These branches enter the ventricular wall and branch extensively. 34. To form purkinje fibres 35. which run throughout the ventricular myocardium. 36. It involves in rapid transmission of impulse through the walls of ventricles. 37. cardiac contractions get initiated by impulse generated by cardiac muscle itself myogenic contractions. 38. SA node get stimulated when auricles become filled with blood. 39. It keeps the basic rhythm of heart beat 40. Therefore, it is known as the ‘pace maker’. 41. contractile impulses, generated at SA node sweep through auricular walls 42. making both aucles contract at once. 43. Simultaneously, being stimulated Auricular-Ventricular Node 44. generate impulses 45. and transmit impulses through bundle of His branches and perkinje network. 46. finally to the muscle fibers of ventricular myocardium. 47. Both ventricules contract together.

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Gross structure

a

p

q

bc

d

e

fg

h i

j k

m

n

a - Pulmonary Semilunar valves b - right Auricle c - right Auricular - ventricular valve/ tricuspid valve d - right ventricle e - Papillary muscle f - Auricular - ventricular septum

g - Aortic Semilunar valves h - Chordae tendinae i - left ventricle j - left Auricular - ventricular valve/ bi cuspid valve k - left Auricular m - Pulmonary veins (left) n - Pulmonary Artery p - Aorta q - Superior/ inferior vena cava

Fully labelled, correct diagram - 15Partially labelled, correct diagram - 5

Any 45 × 3 = 135Diagram 15 150

q

7. (a) What is meant by the growth of plants? 1. The irreversible increase of 2. Dry weight or volume 3. Related to the development of the plant 4. Take Place due to the action of meristamatic tissues

(b) Classify the meristamatic tissues of pants according to the location and write one example for each. 1. Apical meristems 2. Eg: Shoot apex 3. Root apex 4. intercallary meristems 5. Eg: leaf bases 6. bases of internodes 7. lateral meristems 8. Eg: vascular cambium 9. cork combium

(c) Describe the primary tissue structure of a dicot stem. 1. outermost layer is epidermis 2. It is single layered 3. Consists of rectangular / barrel shaped cells 4. Stomata present on the epidermis 5. Cuticle is located outer to epidermis 6. Cortex located inner epidermis 7. At the periphery of cortex

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8. Collenchyma is present 9. Interiorly parenchyma is located 10. Chloroplasts present in collenchyma cells 11. inner to the cortex , annule of vascular bundles is present 12. primary phloem at the periphery 13. inner primary xylem 14. intrafascicular cambium in between xylem and phloem 15. This is known as open vascular bundle 16. collateral vascular bundle 17. xylem is endarch 18. central region consist of pith 19. primary medullary rays in between vascular bundles

epidermiscortexprimary phloemintrafascicular cambium primary xylem

pith primary medullary rays whichconnect cortex and pithcollenchymasclerenchyma

(d) Mention, how the primary monocot stem structure differs from the primary structure of the dicot stem. 1. Circularly arranged vascular bundles are present in docot stems but vascular bundles are scattered in monocot stem 2. The ground tissue is differentiated in dicot stems but there is a ground tissue in monocot stems inner to epidermis. 3. There is distinct pith in dicot stem but pith is absent in monocot stem. 4. The number of vascular bundles in dicot stem is lesser but greater in moncot stem. 5. Cambium present in the vascular bundles of dicot stems but absent in monocot stems (Open vascular bundle in dicot stem closed in monocot). 6. Collenchyma present inner to epidermis of dicot stem but absent in monocot stems 7. Sclerenchymatons bundle sheath present around monocot vascular bundles but absent indicot vascular bundles.

4 + 9 + 19 + 7 = 39any 35 × 4 = 140fully labelled correct diagram = 10partially labelled correct diagram = 5unlabelled correct diagram = 3

150

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8. (a) What are the groups of microorganisms used in industries? 1. Bacteria 2. fungi 3. Algae 4. Viruses ^4 × 2 marks&

(b) Name the occasions in which the microbial process are commercially used as end products and briefly explain each. 1. composting/ production of compost 2. Biogas production 3. extraction of metal like copper from low grade ores. 4. obtaining fibre from plant matter / coir retting 5. Bio remediation 6. composting 7. and release nutrients is utilized here. 8. The natural ability of microorganism 9. Under warm 10. Moist 11. Aerobic conditions 12. A mixed population of microorganism 13. To decompose (Organic matter) 14. The activities of natural microbial population in soil are used here.

Biogas production 15. A gas produced by the biological breakdown of 16. Organic matter 17. In the absence of oxygen/ under Aerobic conditions

Extraction of metals 18. Autotrophic bacteria such as 19. Thiobacillus ferroxidans and 20. Thiobacillus thiooxidans are use to 21. extract metals like copper from low grade ores. 22. They produce H2SO4 and 23. Fe3+ 24. in their metabolic processes. 25. Convert Cu in to CuSo4, (immobilize copper) 26. By oxidizing ores 27. This process is known as microbial Leeching 28. Copper is extracted by 29. Electrolyzing CuSo4

Obtaining fiber from plant materials 30. heterogeneous group of microorganism both 31. aerobic and anaerobic are used here 32. plant materials are immersed in water for 33. varing lengths of time 34. mainly pectinase enzyme, secreted by microorganisums 35. is used to loosen plant mater and coir is seperated.

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Bio remediation 36. The ability of microorganisms to degrade and 37. remove wastes is used here 38. Bioremediation is a catalytic action of microorganisms 39. on pollutants and 40. Remedy or 41. eliminate environmental pollutants 42. this is a natural or 43. managed process is currently used to 44. Accelerate waste water decomposition in chemical plants and 45. industrial food processing plants. 46. to decreases organic waste contents in aquatic environment 47. to remove oil spills from aquatic environments 48. to accelerate composting process 49. to remove toxic metals like chromium, lead, murcury from 50. metal industry wastes. (Any 48 × 3 = 144)

(144 + 8 = 152) (max 150)

9. (a) Briefly describe the theory of biochemical evolution which explains the origin of life on earth. 1. This theory was put forward by Alexander Oparin and J.B.S Haldane 2. Experimental evidences were supplied by Stanly Miller. 3. According to this theory life has been originated on the earth 3.5 billions of years ago. 4. Life could be originated from organic molecules 5. generated in early atmosphere from inorganic gases 6. Combined due to the natural 7. Physical and 8. Chemical laws 9. Early atmosphere was in specific composition (it was lack of oxygen/ reducing atmosphere) 10. It consisted of Hydrogen 11. Ammonia 12. Methane 13. Hydrogen sulphide 14. Carbon dioxide 15. Water vapour like gases 16. due to energy given by (UV) radiation of solar radiation (cample solar energy) 17. Violent volcanic erruptions 18. Heat from radioactive decay 19. lightening from intensive electrical storms 20. Simple organic compounds could have formed 21. from simple inorganic molecules/gases 22. These substances dissolved in the ocean water 23. reacted with each other furthermore. 24. Complex organic compounds could have formed by simple organic compounds such as 25. Amino acids 26. Nitrogenous bases 27. Simple sugar 28. Nucleotides 29. Ocean water containing abundant organic molecules resembled an organic soup./ primodial soup. 30. Organic molecules, being selected on natural reasons

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31. became surrounded by a lipid layer 32. would have evolved into the primitive cells. 33. These priamtive cells possessed growth and 34. self replication like live characteristics. 35. The first formed organisms on earth are believed to be heterotropic, anaerobic,prokaryotes.

(b) Explain the significance of mutations in evolution of bio-diversity. 36. The heritable changes that take place in the 37. genetic material /DNA/genome of organisms is called mutations. 38. Mutations cause to occurrence of new combinations of characteristics /variations. 39. Some mutations are favorable / advantageous 40. favorable mutations are advantageous for the existence / reproduction of organisms. 41. Organisms with favorable mutations win the struggle for existence / in the competition for limited resources. 42. They reproduce successfully and transmit the favorable characteristics to the next generation. 43. Some mutations are unfavorable/ disadvantageous 44. Such mutations are disadvantageous for their existence/ reproduction 45. Organisms with unfavorable variation are not successful for the struggle for existence. 46. They die before reproduction / They don't get chances for reproduction. 47. Organisms with unfavorable variations get failed in the competition 48. Survival of fittest take place /existence of organisms with favorable characteristic is ensured. 49. With the passege of long period when they become unable to carry out fertile reproduction with the original population and produce fertile organisms. 50. Origin of new species. ^50 × 3 = 150 marks&

10. Write short notes on, (a) Functions of human skin 1. Protect the body from 2. dehydration/ friction/ UV radiation. 3. by keratinized cell layers in epidermis. 4. Prevent water loss through epidermis. 5. due to melanin in epidermal cells. 6. UV protection is given. 7. The skin is important as a sensory organ. 8. Pressure. 9. Temperature/ pain are receptors included in the skin 10. skin is important to regulate body temperature 11. by secreting sweat by sweat glands. 12. by dialation and constriction of dermal blood vessels. 13. skin performs an excretory function 14. Sebum secreted by sebaceous glands 15. keeps skin surface/ hair 16. Water proof/ flexible 17. Protect from microbes 18. Skin is important to produce vitamin D. ^Any 17 × 3 = 51) (Max 50&

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(b) Plant movements 1. done by plants as responses for external stimuli 2. Tropic movements 3. Nastic movements 4. Tactic movements

Tropic movements 5. direction of response is determined by the direction of stimuli 6. those are growth movements 7. irreversible 8. shown by a part of the plant/ point of the plant 9. phototropic movements 10. geotropic movements 11. thigmotropic movements

Nastic movements 12. the direction of response isn't determined by the direction of stimulus/ movement done in interminate directions 13. those are either growth or 14. Turgor movements 15. growth movements are irreversible 16. turgor movements are reversible 17. Eg : for growth movements - opening and closure of flowers 18. Eg : for turgor movements - Thigmonastism/ for touch 19. Nictinastism

Tactic movements 20. The entire organism involves in the movement 21. Chlamydomonas movement or movements of gametes of higher plants. ^Any 17 × 3 = 51)

(c) Major conventions and protocols contribute in the conservation of environment. 1. Basel convention 2. to control the transboudary movements of 3. hazardous wastes and 4. their disposal 5. This airm to protect human health and 6. environment against 7. adverse effects of hazardous wastes. 8. Marpol convention 9. the international convention for the prevention of pollution by ships 10. Montreal protocol 11. related on substance that deplete the ozone layer. (to limit the usage of) 12. the aim is limiting or controlling the production of CFC like unfavourable gases. 13. Kyoto protocol 14. an international agreement based on climatic changes. 15. Mainly focussed to reduce green house gas emissions. (18 + 21 + 15 = 54) (Any 50 × 3 = 150)

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