SAMPLE QUESTION—X1

TIME-3Hrs MAX-MARKS---70INSTRUCTION:- SECTION-A contains 8 questions of o1 mark each.SECTION-B contains10 questions of 02marks each.SECTION-C contains 09 questions of 03 marks each.SECTION –Dcontains 03 questions of o5 marks each.

SECTION-AQ1-What is a polysome?Q2-Name the disorder caused due to prolonged hyperglycemia?Q3 -Name two contractile proteins?Q4 -Define serum?Q5-Name the excretory organ of cockroach, earthworm?Q6-Define mosaic vision ?Q7-What is Typhlosole?Q8-Name two natural auxins?SECTION-BQ9-Give any four clinical symptoms of cretinism?Q10-Bring out the differences between red muscle fibres and white muscle fibres?Q11-Draw a structure of mitochondria and label the various parts. OR Draw a sectional view of chloroplast.Q12-Write two modifications of leaves other thanperforming photosynthesis with suitable examples.Q13-Differentiate between early wood and late wood?Q14-What is quiescent phase in cell cycle?Q15-Why is abscisic acid known as stress hormone?Q16-Whatis diatomaceous earth? Write its two commercial use.Q17-What do you understand by heterocyst?Where can we look for it?Q18-Give the full form of ECG.What does QRS complex represent?

SECTION-CQ19-What is competitive inhibitor? Give one example of it.What is its significance in the human body?Q20-Write the steps involved in the absorption of fatty acids and glycerol in the human body.Q21-Explain briefly the different kinds of co-factors with example of each.Q22-Draw a diagram of human eye. OR Draw a diagram of human brain.Q23(A)-Name the first stable product of C3 and C4 cycles.(B) Show the Z scheme of light reaction.Q24-Explain the different steps involved in the formation of root nodule.Q25-How is CO2transportedin the blood?Name the enzyme responsible for it.Q26-What is periderm?How does periderm formation takes place?Q27-Differentiatebetweenacoelomates , coelomates and pseudo coelomates with one example.SECTION-DQ28Name the intermediate compound of glycolysis and TCA cycle.Draw the citric acid cycle. ORQ29-What are synovial joints?Name the different types of joints with one example. OR Write the steps involved in urine formation.Q30-Prepare a list of five organism s that are found parasitic in human beings. Write the names of diseases caused by them.OR [i]Which is the largest phylum of Animalia? [ii]Write four unique features of that phylum. [iii]Give two economic importance with organisms of the same phylum.

MARKING SCHEME1-Group of ribosomes attached to a single mRNA. ( 1)2-Diabetes mellitus.( 1)3-Actin,Myosin. (1).4-Straw coloured fluid that oozes out of a blood clot. (1)

5-Malpighian tubules, Nephridia (1)6-Kind of vision in compound eyes where number of images of the object are formed (1)7-Internal median fold of dorsal wall of alimentary canal between segments 26-35 in earthworms (1)8-Indole -3-acetic acid and Indole-3-butyric acid (1)9-(a) stunted growth (b)mental retardation (c) abnormal skin (d) dwarfism 1/2x4=210-Any two difference 1x2=211-Labelled diagram( any four labeling) 1/2x4=212-Any two points 1x2=213-Any two difference 1x2=214-An inactive stage in cell cycle. OR any correct definition (2)15-Any two points 1x2=216-It refers to the deposits of indestructible siliceous cell wall of diatoms in the ocean floor. Any two uses (1+1/2x2=1)17-Correct definition (1) Are found in certain cyanobacteria like Nostoc and Anabaena (1)18-ECG-Electrocardiogram (1)QRS-represents the simultaneous depolarization of ventricular muscle and repolarization of atrial muscles. (1)19-Correct definition (1) One example (1) Significance (1)20-Fatty acids and glycerol are insoluble, not absorbed into blood first incorporated into micelles,again coated with water soluble materials into globules,again transported into lacteals ,lymph vessels release globules into blood stream. (1/2x6=3)21-Three types of co-factors with examples (1/2x6=3)22-Diagram with correct labeling (1/2x6=3)23- C3 - PGA (1/2) C4-OAA (1/2) Correct diagram with labeling (2)24-Six steps of nodule formation (1/2x6)=3

25-Transport of CO2 occurs in three forms- In dissolved form,asbicarbonates,ascarbaminohaemoglobin. In erythrocytes,carbonic anhydrase catalyses,bicarbonates leak out. (1x3=3)26-Correct definition.Any four steps . (1+1/2x2=2)27-Any three difference with example . (1x3=3)28-Definition (1/2) Different types (2 ½) Examples (2) OR Diagram with proper labeling (2) Glomerular filtration Reabsorption Tubular secrection (1x3=3)29-Acetyl CoA (1)Diagram- (2)Correct labeling- (2) OREMP pathway (1)Steps involved (4)30-Taenia solium--------------------TaeniasisAscaris ---------------------------AscariasisWuchereria-----------------------------FilariasisEntamoeba------------------------------AmoebiasisPlasmodium-------------------------Malaria ORArthropoda (1) Four unique features (2)Any two importance (2).

Dr. Binod Kumar, PGT(Bio), K.V. No.1, BokaroBLUE PRINT

SUB: BIOLOGYCLASS – XI

S. No. UNIT VSA (1 Mark) SA –II (2 Marks) SA – I (3 Marks) LA (5 Marks) Total

1 Diversity in living world 2(2) 2(1) 3(1) -- 7(4)

2 Structural Organization in Animals and Plants

2(2) 4(2) 6(2) -- 12(5)

3 Cell: Structure & Function 2(2) 2(1) 6(2) 5(1) 15(7)

4 Plant Physiology 1(1) 6(3) 6(2) 5(1) 18(7)

5 Human Physiology 1(1) 6(3) 6(2) 5(1) 18(7)

Total 8(8) 20(10) 27(9) 15(3) 70(30)

QUESTION PAPERSUB: BIOLOGY

CLASS – XI

Time: 3 Hours MM: 70 Marks

General Instructions:

(i) All questions are compulsory.(ii) This question paper consists of four sections A, B, C and D.Section A contains 8

questions of one mark each, section B is of 10 questions of two marks each, section C is of 9 questions of three marks each and section D contains 3 questions of five marks each.

(iii) There is no overall choice. However an internal choice has been provided in one question of two marks, one question of three marks and all three questions of five marks weightage. A student has to attempt only one of the alternatives in such questions.

(iv) Wherever necessary the diagrams drawn should be neat and properly labeled.

SECTION A1. Identify the correct scientific name of mango:

1a) Mangifera Indica b) Mangifera indicac) mangifera indica d) mangifera Indica

2. Name the specialized cells of blue green algae which are concerned with nitrogen fixation 1

3. Give the scientific term for a flower which can be divided into two equal halves in any radial plane passing through the centre. 1

4. Name the type of epithelium which is found in ducts of gland. 1

5. Identify the type of ribosome found in prokaryotes: 1a) 80Sb) 90Sc) 70Sd) 60S

6. What do you mean by quiescent stage of the cell cycle? 17. Mention the reaction centre of PS I and PS II. 18. Name the structure of tracts of nerve fibres which connects two cerebral hemispheres.

1

SECTION B9. Give four important characteristics of pteridophytes. 210. What is an exarch vascular bundle? In which part of the plant body it is found? 211. What is typhlosole? Write its function. 212. Distinguish between gram +ve and gram –ve bacteria. 213. What do you mean by water potential? Mention the factors which determine water

potential. 214. Name the nutrients which are concerned with the following: 2

a) Water splitting reaction in photosynthesis.b) Opening and closing of stomata.c) Essential for formation of chlorophyll.d) Synthesis of auxins.

15. What is respiratory quotient? Mention its value for fats. 2

16. Why are human teeth called diphyodont? Write the dental formula of permanent teeth of human. 2

17. How do you differentiate between blood and lymph? 2 18. Expand and define GFR. Mention the value of GFR in a healthy man.

OR Differentiate between cortical and juxta medullary nephrons. 2

SECTION C 19. What is coelom? Differentiate between acoelomate, pseudocoelomate and coelomate

animals with one example of each. 3

20. Write the floral formula and draw floral diagram of the family fabaceae. 3

21. What type of mouth is found in cockroach? Name the various mouth parts of cockroach.

3

22. Briefly explain the primary, secondary and tertiary structure of protein. 3

23. Why is mitosis called equational division? Explain the significance of mitosis. 3

24. Differentiate between cyclic and non-cyclic photophosphorylation. 3

25. Define photoperiodism and distinguish between short day and long day plant. 3

26. Define cardiac cycle and differentiate between first and second heart sound. 3

27. Draw a neat diagram of human urinary system and label any six parts in it.

OR

Draw a neat diagram of human heart and label any six parts in it. 3

SECTION D

28. Explain six classes of enzymes with one example of each.

OR

Describe different phases of prophase I of meiosis with neat and labeled diagram. 5

29. What is glycolysis? Explain glycolytic pathway with graphic representation.

OR

Explain Calvin cycle with graphic representation. 5

30. What is synapse? Explain the transmission of nerve impulse across a synapse with neat labeled diagram.

OR Explain the mechanism of hormone action with neat and labeled diagram. 5

Marking SchemeBiology

Class XI M.M.70SECTION A

1. b) Mangifera indica 12. Bulliform cells 13. Actinomorphic 14. Cuboidal epithelium 15. c) 70S 17. PSI-P700 ½ PSII-P680 ½8. Corpus Callosum 1

SECTION B

9. Each character ½x4=210. Definition 1 Root 111. Definition 1 Function 112. Each difference ½x4=2

13. Definition 1 2Factors 114.a) Chlorine ½ b) Potassium ½ c) Iron ½d)Zinc ½15. Definition 1 Value 116. For Diphyodont teeth 1 Dental formula 117. Each difference ½x4=218. Expansion ½ Definition ½ Value 1

SECTION C

19. Definition 1 Differentiation 1 Example 120. Floral formula 1 Floral Diagram 2

21. Type of mouth 1

Mouth Parts 222. For each structure 1x3=323. Equational division 1 Significance 224. For each difference 1x3=325. Definition 1 Differentiation 226 Definition 1 Each difference ½x4=227. For each labeling ½x6=3

SECTION D

29.Definition 1 Glycolytic Pathway 2 Explanation 230. Definition 1 Diagram 2 Explanation 2

OR Diagram 2 Explanation 3

Blue print

unit VSA1

MARKS

SA2

MARKS

SA13

MARKS

LA5

MARKS

TOTAL

1 DIVERSITY IN LIVING WORLD

1(1) 2(3) - - 7(4)

2 STUCTURAL ORGANISATIO

N IN PLANTS&ANIM

ALS

- 2(2) 3(1) 5(1) 12(4)

3 CELL: STRUCTURE &FUNCTION

4(1) 2(1) 3(3) - 15(8)

4 Plant physiology - 2(2) 3(3) 5(1) 18(6)

5 Human physiology

3(1) 2(2) 3(2) 5(1) 18(8)

TOTAL 8(8) 20(10) 27(9) 15(3) 70(30)

Marking Scheme

Class XISubject-Biology

Section A

1. The bond linking two amino acids in protein. 1

2. a) Pivot joint ½b) Cartilaginous joint/slightly movable joint. ½

3. Many ribosomes attached to mRNA. 1

4.i) Maintains total blood volume. ½ii) Carries protein and lipid macromolecules to blood for circulation.

½

5. Adenine, Guanine. ½+ ½ =16. As L.V sends blood to distant body parts. 17. They have a different cell wall structure. 1

8. Which cell undergoes meiosis? 1Section B

9. Estrogen-follicular cells of ovarian follicle. 1Progesteron –corpus luteum. 1

10.a-Robert Brownb-schleindon and schwann.c-fluid mosaic model of cell membrane.d-golgi apparatus. ½X4=2

11)correct reasons. 1+1=2

12)correct diagram and labelling. 1+1=2

13)carboxylaseRuBP+CO 2X3 PGAOxygenaseRuBP +O2 PGA +Phosphoglycolate1+1=2

14)4 correct rules 1/2x4=2

15)for correct differences. 1+1=2

16) a)Stem has collateral VB,root has radial arrangement of VB.b)In dicot stem VB arranged in a ring In monocot stem VB scattered. In root VB arranged radially 1+1/2+1/2=2

17) Two correct reasons1+1=2

18)Correct definition. 1 Two functions 1/2X2=1

Section C

19)correct explanation of mono,di, triglycerides 1x3=3

20)correct drawing and labeling of 6 parts. 1/2X6=3

21)correct description of primary, secondary and tertiary structure. 1X3=3

22 i)mitoticanaphase,anaphase 1 of meiosis 11ii)correct points of difference. 1iii)correct number of chromosomes 1/2+1/2=1

23)correct definition of each of three. 1X3=3

24)correctexplaination of the each. 1+1/2x2=3

25)yes it will carry out photosynthesis 1Two important functions of other pigments 1+1=2

26)Terrestrial amphibians, Marine fishes ½+1/2=1Two correct point of differences 1+1=2

27) Drawing and description of three types of neuron 1+1+1=3

Section-D

28)a) Auxin

b) Ethylenec) Cytokinined) ABA 1x5=5e) GA3

OR

Correct definition 13 categories of Plants 1X3=3Name of hormone 1

29. Correct description of digestion of Carbohydrates 3Correct answer of end product absorption 2

OR

Correct diagram and labeling of the parts 1/2X10=5

30.i. Metaphase

ii. Anaphaseiii. Zygoleni of prophase Iiv. Pachytenev. G2 Phase 1X5=5

OR

Correct diagram & labeling of 5 substages of Prophase 1 1/2x10=5

Sample Question Paper

Class : XI Max. Marks : 70

Sub : Biology Time : 3 Hours

General Instructions :

(i) All questions are compulsory.(ii) The question paper consists of four sections – A, B,C & D. Section A contains 8

questions of 1 mark each, Section B contains 10 questions of 2 marks each , Section C has 9 questions of 3 marks each , whereas Section D has 3 questions of 5 marks each.

(iii) There is no overall choice.However,an internal choice has been provided in one question of 2 marks &allthe three questions of 5 marks weightage.A student has to attempt only one of the alternatives in such questions.

SECTION – A

1. What is a peptide bond ?2. Name the type of joint between

(i) Atlas & axis (ii) Successive vertebrae

3. What are polysomes ?4. Mention two functions of lymph?5. Name two carbon compounds where heterocyclic rings are found.6. Why is left ventricle more muscular than the right ventricle ?7. How are archaebacteria able to live in the extreme environmental conditions ?8. What is a meiocyte ?

SECTION –B

9. Name the two ovarian hormones. Name the part of the ovary from where each is secreted .

10. Fill in the blanks :

A Nucleus

B Cell theory

Singer & Nicholson CCamillo Golgi D

11. How is the gut lining protected from its secretion of proteases ?

12. Draw a labelled diagram of “ Nostoc “.

13. Rubisco acts as carboxylase &oxygenase. Describe their functions.

14. Enumerate the universal rules of nomenclature.

15. How are the cardiac muscles different from striated muscle ?

16. You have been given a slide showing transverse section of astem or a root.Giving one reason explain how would identify that :a) Whether the slide is of a stem or a root b) Whether the slide is of a dicot plant or a moncot plant

17. Give two reasons to justify onion is amodified stem.

18. What is mesosome in a prokaryotic cell ? Give its two functions .OR

Name and differentiate between the two types of ribosomes.

SECTION – C19. Explain the term monoglycerides, diglycerides, & triglycerides.

20. Draw a diagram of the alimentary canal of cockroach and label any six parts.

21. Describe briefly the primary ,secondary& tertiary structure of proteins.

22. Study the diagrams (a) & (b) given below and answer the following questions :

(a) (b)

(i) Name the type of cell division and its phase shown in diagram (a) & (b)(ii) Distinguish between these two phases of cell division.(iii) What would be the number of chromosomes in each daughter cell after

complete cell division in each case.23. Define the following:(i)Isotonic (ii) Hypertonic (iii) Hypotonic24. How does oxidative phosphorylation differ from photophosphorylation ? Explain.25. Suppose there were plants that had a high concentration of chrolophyll‘b’ , but

lacked chlorophyll’ a ‘, would it carry out photosynthesis ? Then why do plants have chlorophyll ‘b’ & other accessory pigments ?

26. Fromthe following groups of animals select which are ureotelic - Terrestrial amphibians , aquatic amphibians marine fishes & reptiles.How would you distinguish ureotelism from uricotelism.

27.Describe the three types of neurons based on the number of axons and dendrons/ dendrites.

SECTION –D

28. Which one of the plant growth regulator would you use , if you are asked to :a) Induce rooting in a twigb) Quick ripening of a fruitc) Delay in leaf senescenced) Induce immediate stomatal closure in leaves e) Increase length of a dwarf plant

OR

Define photoperiodism. Explain with examples the three categories of plants, based on photoperiodism. Name one hypothetical hormone , which is supposed to induce flowering in plants.

29.Describe digestion of carbohydrates in human alimentary canal.How are the end products of carbohydrate digestion absorbed ?

OR

Draw a schematic diagram of the cross-section of spinal cord alongwith knee-jerk reflex arc, showing one efferent and two afferent fibre path rays. Label any ten parts of it.

30.Name the stage of cell cycle, at which each of the following events occur :

(i) Chrosomes are moved to spindle equator.

(ii) Centromere splits and chromatids separate.

(iii)Pairing between homologous chromosomes takes place.

(iv)Crossing over between homologous chromosomes takes place.

(v)Phase in the cell cycle when protein & RNA are synthesized

OR

Show diagrammatically the events in prophase I , with complete labelling.

PREPARED BY: PRATAP SINGH CHARAN

PGT –BIOLOGY

KV -PASIGHAT

Blue print class XI- BIOLOGY

UNIT NO NAME OF UNIT K U S A

TOTAL

1 2 3 5 1 2 3 5 1 2 3 5 1 2 3 5

I Diversity in living World 1 2 3 1 7

IIStructural organization in Animals and plants 1 3 1 2 1 3 1 12

III cell structure and Function 2 3 5 2 3 15

IV Plant Physiology 2 5 1 3 2 3 2 18

V Human Physiology 2 3 2 3 5 1 2 18

2 6 910 2 8

12 5 1 2 6 3 4

total 27 27 9 7 70

% 38.6 38.6 12.9 10.0 100

Biology

Time: 3hours Class –XI MM: 70

All questions are compulsory and marks are shown against them.

Section (A) consists of questions Q 1-8 of 1 mark each. Section (B) consists of questions Q 9-18 of 2 marks each. Section (C) consists of questions Q 19-27 of 3 marks each. Section (D) consists of questions Q 28-30 of 5 marks each. An internal choice has been provided in one question of 2 marks, one question of 3 marks,

and all the three questions of 5 marks.

Section – (A)

Q1- Name the two type of modification of root found in the followinga) Banyan tree.b) Mangrove trees.

Q 2 The following figure shows an alveolus with a capillary in close contact.

a) What is gas 1 and gas 2?b) What is the name of the process by which these gases move between the blood and the

alveolus?Q 3 Write one economically important use of Archaebacteria?

Q 4 What is the life cycle with dominant diploid adult and gametic meiosis called?Q5 What is a dikaryon and where does it occur?

Q6 Name the two plant groups which bear archegonia.

Q 7 Draw a diagram to show conjoint closed vascular bundles.

Q 8 What is a chondriocyte and where is it found?

Section – (B)

Q 9 Distinguish between the following:

a) Actin and myosin.b) red and white muscles

Q10 Write the correct taxonomic categories of man against genus, family, order and phylum. Q11What is RQ? Calculate the value of RQ for tripalmitin when used as substrate. 2(C51H98O6) +145O2 ----102CO2 +98H20+energyQ12 Mention any protein having quaternary structure. Name the polypeptide chains also.Q 13 Write any two points of differences between monocot and dicot stem.

Q 14 Explain a nucleoside and a nucleotide.

A B

Q 15 Name the structures A-B and also explain why the wall of the left ventricle is thicker than the wall of the right ventricle?

Q 16 Draw a well labeled diagram of an eye to show its internal structure.

Q 17 Distinguish between cyclic and non cyclic photophosphorylation. (Two points)

OR

Write any two points of differences between C3 and C4 plants.

Q18 which one of the growth regulators would you use if you are asked to:

A. Quickly ripen a fruit.B. Promote nutrient mobilization.C. Induce immediate stomatal closure.D. Induce parthenocarpy.

Section –(C)

Q 19 Explain the structure of a monocotyledonous seed with a suitable diagram.

Q 20 Draw a neat diagram of digestive system of frog.Q 21 Explain with a diagram the three important stages of Kelvin cycle.

OR

Write the schematic representation of an overall view of Krebs’s cycle.

Q 22 Which hormone is responsible for the following:

a) Gigantism.b) Diabetes mellitus.c) Cretinism

Q 23 a snake, a crocodile and a chameleon all belong to the same class of phylum chordate. Name the class and its two important features.

Q 24 Illustrate a glycosidic, peptide and a phospho-diester bond.

Q 25 Draw the schematic representation of the various steps of conversion of atmospheric nitrogen to ammonia by nitrogenase. How is this enzyme protected in the root nodule?

Q 26 Distinguish between the following:

a) Blood and lymph.b) Systole and diastole.c) Ligament and tendon

Q27 What is a centromere? How are the chromosomes classified?

Section – (D)

Q 28 Define photoperiodism. Explain with examples the three categories of plants based on photoperiodism. Name the hypothetical hormone which is supposed to induce flowering.

OR

Differentiate between the following:

a) Osmosis and diffusion.b) Active and passive transport.c) Guttation and transpiration.

Q 29 Explain the process of urine formation in mammals with a suitable diagram.

OR

Explain different stages of axon membrane during the transmission of a nerve impulse along a nerve fibre. (Non-myelinated and myelinated)

Q 30 How are the enzymes classified into various groups? Explain any five groups.

OR

a) Define Synapsis, cofactors and competitive inhibitors.

b) Distinguish Anaphase of mitosis from Anaphase 1 of meiosis along with a diagram?

Biology –Marking Scheme

Time: 3.00 hours Class –XI MM: 70

Section – (A) -1 Mark Each

A1- modified rootsa) Banyan tree-prop roots ½ markb) Mangrove tree- pneumatophores ½ mark

.A 2 gas 1 –O2 and gas 2-CO2 ½ mark

Process- diffusion ½ mark

A 3 Responsible for production of methane (biogas).

A 4 diplontic.A 5 Dikaryon-two nuclei per cell -½ mark, ex –fungi ½ mark

.

A6 Bryophytes and pteridophytes. ½ mark each

A 7 diagram - ½ mark., Xylem and phloem label - ½ marks

A 8 cells of the cartilage - ½ mark, tips of the nose, outer ear - ½ mark.

Section – (B) - 2 Marks Each

A 9 one difference 1 mark each.

Presence and absence of myoglobin -1 mark

A10 genus- Homo, family -Homoinidae, order – Primate, phylum- Chordate ½ mark each

A11 RQ = Volvo CO2 evolved/ vol.of O2 consumed. RQ for tripalmitin when used as substrate. = 0.7 (1 mark each) A12 protein having quaternary structure- hemoglobin. Polypeptide chains Alpha and beta chains. (1 mark each)

A 13 Arrangement of vascular bundles

VB- open and closed (any two -1 mark each).

.

A 14 nucleoside – a nitrogenous base + sugar

Nucleotide. – A nitrogenous base + sugar+ phosphate

A 15 A-aorta, B-pulmonary vein, C- pulmonary artery, D-bicuspid valve. Left ventricle to push the blood over a greater distance.

A 16 diagram of an eye -1 mark, important label -1 mark.

A 17 cyclic –result of PS I, the electrons are recycled or any other.

Corresponding points in non-cyclic photophosphorylation.

OR

Mention of Kranz anatomy (any two points)

A18 growth regulators: ½ mark each

E. Quickly ripen a fruit.- - EthyleneF. Promote nutrient mobilization.- - cytokininG. Induce immediate stomata closure. -ABAH. Induce parthenocarpy. - Axim

Section –(C) - 3 Marks Each

A19 structure of a monocotyledonous seed - suitable diagram -1½ mark.

Labeling - 1½ mark.

.

A 20 neat diagram of digestive system of frog. -1½ mark Labeling - 1½ mark.

.

Or Explain the structure of DNA as given by Watson and Crick.

A 21 important stages of Kelvin cycle”.-carboxylation, reduction, regeneration

(1 mark each ) OR

Krebs’s cycle.-citric acid cycle (3 marks)

A 22 hormone is responsible for the following: (1 mark each)

d) Gigantism. –Growth hormonee) Diabetes mellitus. - Insulinf) Cretinism -Thyroxin

A 23 class -Reptilia. 1 mark Important features.-dry and cornified skin (epidermal scales), creeping or crawling habit, heart

usually 3-chambered, (any two points) (2mark)

A 24 Definition: ½ mark illustration: ½ mark

c) glycosidic, d) peptide

e) Phospho-diester bond. 25 schematic steps of conversion of atmospheric nitrogen to ammonia by nitrogenase. (2 mark) Enzyme protected in the root nodule- by leg –hemoglobin. (1 mark) A 26 one difference each: (1 mark each)

d) Blood and lymph.e) Systole and diastole.f) P-wave and T-wave

A 27 centromere – definition (1 mark each)

Chromosomes classification, 4 types (- ½ mark.)

Section – (D) 5 Marks Each

A 28 photoperiodism.-definition (1 mark)

Three categories of plants (3 marks)

Hormone supposed to induce flowering.-Florigen (1 mark)

OR

Differences between the following:

d) Osmosis and diffusion (2marks) e) Active and passive transport. (2 marks) f) Guttation and transpiration(1marks)

A 29 urine formation in mammals- glomerular filtration, reabsorption and secretion. (3mark),

Diagram and labeling (2 marks)

OR

Explanation -different stages of axon membrane during the transmission of a nerve impulse along a nerve fiber. (Non-myelinated and myelinated) (3 mark)

Diagrammatic representation- (2 marks)

A 30 enzymes classification into various groups (Explain any five groups)

(1mark each).

OR

a) Definition- Synapsis, cofactors and competitive inhibitors. (1 marks each).

b) Difference between Anaphase of mitosis and Anaphase 1 of meiosis (1 mark)

Diagram (1 mark)

BLUEPRINT OF Q.P. OF CLASS XI-BIOLOGYA.Unit wise distribution of marks :Unit-1:Diversity in the living world 07Unit-2:Structural organization in plants & animals 12Unit-3:Cell structure & function 15Unit-4:Plant physiology 18Unit-5:Animal physiology 18B.Types of questions :

Knowledge Understanding Application Skill No. of ques

Total marks

1x4ques,2x6ques.,3x5ques,5x1ques

1x2ques,2x1ques,3x2ques,5x1que,

1x2ques, 2x3ques,3x1ques,5x1ques

3x1que Total no.ofques =30Total marks =70

No. of ques-16Marks-36

No. of ques-06Marks-15

No. of ques-07Marks-16

No. ofques-01Marks-03

C.Number of questions :Sl no.

Form of question Marks for each ques.

No. of ques. Marks

1. Very short answer (VSA) 01 08 082. Short answer (SA-I) 02 10 203. Short answer (SA-I 03 09 274. Long answer (LA) 05 03 15

TOTAL - 30 70D.Unit-wise distribution of marks :

Types of ques.Units

VSA1 marks

SA-I2 marks

SA-II3marks

LA5 marks

Total

Diversity in the living world 2 (2) 1 (2) 1 (3) -- 07Structural organization in plants & animals -- 2 (4) 1 (3) 1 (5) 12Cell: Structure & functions 3 (3) 3(6) 2 (6) -- 15Plant physiology 2 (2) 1 (2) 3 (9) 1 (5) 18Animal physiology 1 (1) 3 (6) 2 (6) 1 (5) 18Total 8 (8) 10 (20) 9 (27) 3 (15) 70

Marking scheme of Q.P. of Class-XI Section-A1.Cell gets swollen/turgid. 12.Temp. ,light, humidity, windspeed. (anytwo) 13.Pleuro Pneumonia Like Organisms. 14.Ability to emit light 15.Cells that don’t divide enter an inactive stage called quiescent stage(Go). 16.ABA/Abscisic acid. 17.One mol. 18.No rods or cones are present. 1Section-B9.Giving a scientific name with two components. Ex. - Homo sapiens where Homo is the generic name &sapiens is the specific epithet. 1+1=(2) Or Any four rules .1/2x4=(2)10.Peripheral proteins on the surface &integral proteins partially or totally buried in the cell membrane. (2)11.Biological membranes having lipids when broken into pieces form vesicles which are water insoulable. These separate along with the acid insoluble pool in the macro molecular fraction. (2)12.Special membranous structure present in prokaryotic cells & any two functions. (2)13.Correct definition with example. 1+1=(2)14.Any two functions. 1/2x2=1 Any two names . 1/2x2=115.Correct definition & equation. 1+1=(2)16.Anti-diuretic hormone. It increases reabsorption of Na+ & water from DCT. 1+1=(2)17.Pons region of brain. Signals from this centre reduces the duration of respiration & increases the rate of respiration. (2)18.Kidneys help in elimination of nitrogenous wastes ; lungs remove CO2 & water. (2)Section-C19.Arthropoda. Any five features. 1/2x6=(3)20.Neat labeled diagram with six correct labellings. (3)21.Two daughter cells formed with same no. of chromosomes.Any two points. 1+1+1=(3)22.Oxygen scavenger pigment in root nodules; maintains anaerobic condition there. (3)23.Steps of glycolysis. (3)24.Correct definition ; long-day, short-day, day-neutral plants to be explained. (3)25.Non-cyclic photophosphorylation ; ray diagram to be given (3)26.Vit.-K &Ca+ ; steps of blood clotting. (3)27.Stimulates i) glycogenolysis, ii) gluconeogenesis & iii) reduces cellular glucose uptake & utilization. (3)Section-D28.Correct description & mechanism to be given. 3+2=(5) OrLens shaped openings in the bark of trees ; function- gaseous exchange.Differences – any three points. 2+3=(5)29.Correct description of ETS. OrTCA cycle to be given with energy calculation. (5)30.Three steps of urine formation to be given and explained. OrResting membrane potential, depolarization, repolarization to be explained. (5)

CLASS – XI

Sub.: Biology

Time : 3 Hrs F.M.: 70

General Instructions:-

i. All questions are compulsory.ii. This question paper consist of four section A, B, C and D. Section A contains 8

question of one marks each, Section B contains 10 questions of two marks each. Section C is 9 questions of three marks and Section D is of 3 questions of five marks each.

iii. There is no overall choice. However an internal choice has been provided in one question of two marks, one questions of 3 marks and all the three questions of 5 marks.

iv. Whenever necessary, supplement your answer with diagram.

Section: A

1. What will happen to a cell when it is placed in higher water potential? (1)2. Name the factors which effect the rate of transpiration. (1)

3. Expand PPLO. (1)4. What is bioluminescence? (1)5. What is G0 phase? (1)6. Name the hormone that makes the plants more tolerant to various stresses. (1)7. How many ATPs are released when one molecule of Acetyl CoA undergoes TCA cycle?

(1)8. Why is blind spot devoid of vision? (1)

Section: B

9. What is binomial nomenclature? Give an example and explain. (1+1=2)

OR

What are the rules for binomial nomenclature?

10. Describe two types of proteins found in cell membrane. (2)11. Why are lipids included under macro molecules? (2)12. What are mesosomes?Write two functions of mesosomes. (1+1=2)13. What are co-factors? Describe one co-factor with reference to enzymes. (1+1=2)14. i) Mention two functions of cytokinins.

ii)Name two synthetics Auxins. (1+1=2)15. What is R.Q.?Show with an equation that RQ is one for carbohydrate. (1+1=2)16. What is ADH? What is its role in forming hypertonic Urine? (2)17. Where is pneumotoxic center located? How is regulate respiratory rate? (2)

18. What role does kidney and lungs play in excretion? (1+1=2)

Section: C

19. Name the largest phylum in Animal Kingdom. Write five main characteristic feature of this phylum. (3)

20. Draw a labeled diagram of digestive system of cockroach. (3)OR

Draw a labeled diagram of male reproductive system of frog.21. Why mitosis is called equational cell division? Write its significance. (1+2=3)22. What is leg-haemeoglobin?Where is it found? Write its importance.

(1+1+1=3)23. Describe different steps in glycolysis.

(3)24. What is photopreiodism?Explain different types of plants with respect to photoperiodism.

(3)25. What is Z-Scheme in photophosphorylation?Explain it with ray diagram. (3)26. Which vitamin and mineral is responsible for clotting of bloods? Enumerate the events

that occur in the clotting of blood. (3)27. ‘Glucagon is called hypercalcemichormaone.’Give reasons. (3)

Section: D28. What is stomatalapparatus?Discuss the mechanism of the opening and closing of stoma.

OR (5)What are lenticels? What is their function? Differentiate between parenchyma and sclerenchyma.

29. Describe electron transport system operating in mitochondria. (5)OR

Describe different steps in TCA cycle with energy calculation.

30. Briefly explain the mechanism of urine formation. (5)OR

How is nerve impulse transmitted along a mylelinated nerve fibre.

----000-----

BLUEPRINT OF Q.P. OF CLASS XI-BIOLOGY

A.Unit wise distribution of marks :Unit-1:Diversity in the living world 07Unit-2:Structural organization in plants & animals 12Unit-3:Cell structure & function 15Unit-4:Plant physiology 18Unit-5:Animal physiology 18B.Types of questions :

Knowledge Understanding Application Skill No. of ques

Total marks

1x4ques,2x6ques.,3x5ques,5x1ques

1x2ques,2x1ques,3x2ques,5x1que,

1x2ques, 2x3ques,3x1ques,5x1ques

3x1que Total no.ofques =30Total marks =70No. of ques-16

Marks-36No. of ques-06Marks-15

No. of ques-07Marks-16

No. ofques-01Marks-03

C.Number of questions :

Sl no.

Form of question Marks for each ques.

No. of ques.

Marks

1. Very short answer (VSA)

01 08 08

2. Short answer (SA-I) 02 10 203. Short answer (SA-I 03 09 274. Long answer (LA) 05 03 15

TOTAL - 30 70D.Unit-wise distribution of marks :

Types of ques.Units

VSA1 marks

SA-I2 marks

SA-II3marks

LA5 marks

Total

Diversity in the living world 2 (2) 1 (2) 1 (3) -- 07Structural organization in plants & animals

-- 2 (4) 1 (3) 1 (5) 12

Cell: Structure & functions 3 (3) 3(6) 2 (6) -- 15Plant physiology 2 (2) 1 (2) 3 (9) 1 (5) 18Animal physiology 1 (1) 3 (6) 2 (6) 1 (5) 18Total 8 (8) 10 (20) 9 (27) 3 (15) 70

BIOLOGY QUESTION PAPER CLASS11KENDRIYA VIDYALAYA NO.2 SALTLAKE KOLKATA.Subject – BiologyClass - XI

Time : 3 hours Max.Marks 70

General Instructions:

1. All questions are compulsory.2. This question paper consists of four Sections A, B, C and D. Section -A contains

8 questions of 1 mark each, Section -B is of 10 questions of 2 marks each, Section -C has 9 questions of 3 marks each and Section D is of 3 questions of 5 marks each.3. There is no overall choice .However, an internal choice has been provided

in one question of 2 marks, one question of 3 marks and all the three questions of5 marks weightage . Attempt only one of the choices in such questions.

4. Wherever necessary, the diagrams drawn should be neat and properly labelled.

SECTION AQ.1Who gave the system of providing a name to an organism with 2 components? What are the 2 components?Q2.WHICH TISSUE IS PRESENT in the petiole of a leaf & what causes hardness in the pulp of certain fruits such as pea?Q3 what is residual volume? Give capacity in human adult.Q4NAME 2 vitamins that contain sulphur?Q4 Define plasmolysis?SECTION BQ6 How are heart sounds produced during cardiac cycle?Q7 what is meant by apoplastpathway?why does it occur in cortex & not in endodermisQ8 Differenciate between dicot &moncot root.Q9 Name the end products of Aerobic & Anaerobic glycolysisQ10. How areAscomycetes different from basidiomycetes

Q11 How many cells are present in the egg apparatus of plant.Q12 What are the functions of golgi bodiesQ13 Give difference between Anaphase1 & anaphase 2Q14 Describe GoutOrName the source & function of ADHQ15. How do rods and cones differ chemically &functionally.

SECTION-C

16. Define activation energy of a reaction. Give the four steps of catalytic cycle of a enzyme action.17. What do you mean by reflex action? Give the diagrammatic presentation of reflex action.18. With which animal or phylum can you relate the following terms: a) Radial symmetry b) Haemocoel c) Setae d) Water vascular system. e) Radula f) Pneumatic bones.19. Draw the labeled diagram of fluid mosaic model of plasma membrane.Or Draw the well labeled diagram of typical plant cell.20. a) Give two uses of Auxin. b) Define Vernalisatio. c) Define Redifferentiation.21. Name the different types of Leukocytes. What is SA node? Why is it called pacemaker of heart?22. a) Draw floral diagram of Solanaceae.

b) Give floral formula of Fabaceae.c) Give the symbols of actinomorphic and zygomorphic flowers.

Ora) What is Phyllotaxy? What kind of Phyllotaxy is present in China Rose?b) Give one major difference between Racemose and Cymose inflorescence.c) Name the plants with stem tendrils.

23. Differentiate between three types of muscular tissue presne tin our body.24. Describe the steps in Biological Nitrogen Fixation.25. a) What do you mean by respiratory quotient?

b) What is ‘Coleoptile’ and Coleorrhiza?c) Give the role of Bulliform cells.

SECTION-D

26. Describe the process of urine formation in mammals.

OrDescribe the digestion of carbohydrates in human alimentary canal. How are the end products of carbohydrate digestion absorbed?27. Which are the three phases of calvin cycle? Draw the schematic diagram of Calvin cycle. Why C4 plants are preferred to C3 plants?OrDraw the schematic diagram of Kreb’s cycle. Give the role of citric acid cycle in living organisms.28. a) Explain the various stages of Prophase I in Meiosis.

b) Give one difference between spring wood and autumn wood.c) How does cytokinesis in plant cell differ from that in animal cell?

Answers1. Linnaeus. The two components of the name of an organisms are the Generic name and specific name.2. Sclerenchyma. Sclereids cause grittiness in the pulp of certain fruits.3. Residual volume refers to the volume of air left in the lungs, even after forceful expiration. It is about 1500 ml.4. Biotin, Thiamine.5. Plasmolysis is the shrinking of the protoplast and its movement away from the cell wall due to exosmosis, when the cell is place in a hypertonic solution.6. The two heart sounds are ‘lubb’ and ‘dupp’.---The first heart sound ‘lubb’ is produced by the closure of AV-vaves at the start of ventricular systole.---The second heart sound ‘dupp’ is produced by the closure of semilunar valves at the start of ventricular diastole.7. Apoplast pathway:--- Movement of water occurs exclusively through the cell wall and intercellunar spaces; it does not cross any membrane or living component of the cell.---This type of movement occurs in the cortex, as cortical cells are loosely arranged and offer no resistance.---But endodermis has casparian strips made of suberin; it is impervious to water and so water is forced to follow the symplast pathway.8. Differences:Dicot stem Dicot root---Vascular bundles are radial.---Xylem is endarch.---Vascular bundles are open, i.e., cambium is present.

---Vascular bundles are conjoint and collateral.---Xylem is exarch.---Vascular bundles are closed, i.e., cambium is absent.

9. The end products of glycolysis are two molecules each of i) phyruvic acid, ii) NADH and iii) ATP. ATP is formed in the following two ways:

i) by direct transfer of phosphate to ADP(substrate phosphorylation) and

ii) by oxidation of NADH produced in glycolysis to NAD, in the electron transport system(oxidative phosphorylation)

10. Differences:

Ascomycetes Basidiomycetes---They produce fruiting bodies called ascocarp.---Each ascus contains eight ascospores within.(endogenously)---They may or may not show dikaryotic phase in the life cycle.---Asexula spores are found.

---They form fruiting bodies called basidiocarp.---Each basidium produces four basidiospores exogenously.---They show an extended dikaryotic phase in the life cycle.---Asexual spores are not found.

11. Egg apparatus of angiosperms cantains three cells; they are i) female gamete or egg cell, and two synergids. The other components are three antipodal cells and two polar nuclei.12. Functions of Golgi complex:

a) It packages the materials for intracellular tgransport as well as for secretion to the outside.

b) Many proteins synthesized by the ribosomes are modified in the cisternaeof Golgi apparatus.

c) It is the site of formation of glycoproteins and glycolipids.d) Golgi cisternae form the primary lysosomes by budding.

13. Differences: a)

b)

14. a) Myasthenia Gravis

---It is an autoimmune disorder that affects the neuromuscular junctions.---The skeletal muscles become fatigued, weak and paralyser.b) Gout---Gout refers to inflammation of joints due to accumulation of uric acid crystals.

15. Differences:

‘S’ phase ‘G1’ phase---In this substage of interphase, there is replication of DNA; the amount of DNA in a cell becomes doubled.

---It is the first substage of interphase, where there is synthesis of RNAs and proteins.Anaphase I Anaphase II

---The centromeres do not divide and os one whole chromosome moves to the pole.

---The centromere divides, and one half of a chromosome moves to one pole, while the other half moves to the opposite pole.

16. The

difference in the average energy content of the substrate, from that of the transition state structure, is called activation, i.e., the energy needed to initiate a reaction. The four steps of catalytic cycle of an enzyme action:

a) The substrate binds to the active site of the enzyme.b) This binding of the substrate induces the enzyme to alter its shape and fit more

closely around the substrate.c) The active site of the enzyme, now in close proximity of the substrate breaks the

chemical bonds of the substrate and an Enzyme-product complex is formed.d) The enzyme releases the product(s) of the reaction and the free enzyme is ready to

take up another molecule of the substrate.

17. Reflex ActionA reflex action may be defined as a spontaneous involuntary nerve-mediated activity

produced at the unconscious level by stimulating specific receptors.Stimulus – Receptor – Sensory nerve – Spinal cord (intermediate/connecting neuron) –

Motor nerve – Effector.18. a) Phyla Echinodermata and Cnidaria

b) PhylumActhropodac) Phylum Annelidad) Phylum Echinodermatae) Phylum Molluscaf) Phylum Chordata, class : Aves.

19. Diagram…….

20. a) Uses of auxin: i) Control of preharvest drop of fruits. ii) Development of parthenocarpic fruits.

iii) Thinning of flowers and fruits for healthy growth of the remaining ones.iv) Enhancing flowering and thereby fruiting.

(Any two)b) Vernalisation is the phenomenon is which soaked seeds or seedlings are exposed to

very low temperatures to induce early flowering.

Rods Cones---These are more sensitive to light are meant for vision in dim light(scotopic vision).---They do not have the ability to make coloured image.---These contain the visual pigment rhodopsin.

---These are meant for vision in bright light(photopic vision).---They have the ability to make coloured image.---These contain the pigment iodopsin.

c) Redifferentiation is the process by which the cells produced by dedifferentiated cells undergo changes in their shape and structure, according to the function they perform.

21. LeucocytesGranulocytes(Eosinophils, Basophils and neutrophils) and Agranulocytes(Lymphocytes, monocytes).

SA-node---It is a patch of specialized cardiac muscles, located in the right upper corner of right atrium that initiates the cardiac impulse.---It is called the pacemaker because it determines the rate of discharge of cardiac impulse and thereby determines the rate of heart beat.

22. a) Diagram……b) ………………..c) Actinomorphic flowers Zygomorphic flowers %

Ora) Phyllotaxy refers to the mode of arrangement of leaves on a stem/branch. ---In China Rose, phyllotaxy in alternate.

b) Differences:Racemose Inflorescence Cymose Inflorescence---In this substage of interphase, there is ---The terminal bud of the inflorescence axis continues to grow, i.e., the main axis has unlimited growth.---Flowers are arranged in an acropetal order, i.e., older flowers are towards the base while the younger flowers are towards the apex.---Flower opening is centripetal, i.e., peripheral flowers open first and then central flower.

---It is the first substage of interphase, where ---The terminal bud of the inflorescence axis forms a flower, i.e., the main axis has limited growth.---Flowers are arranged in a basipetalsuccession, i.e., older flower is towards the apex and younger flowers are towards the base.---Flower opening is centrifugal, i.e., the central flowers open first and then those at the periphery.

c) Cucurbita and Vitis.

23. Three types of muscular tissues: Skeletal / Striated muscles Smooth / Non- striated

musclesCardiac muscles

i) Striations are prominent.ii) Voluntary in function.iii) Cells are multinucleate.iv) Fibres are cylindrical and unbranched.

v) Innervated by voluntary nervous system.

e.g., Muscles of limbs.

---Striations are absent.---Involuntary in function.---Cells are uninucleate.---Fibres are spindle shaped. Branched and show intercalated discs.---Innervated by autonomic nervous system.

---Muscles of visceral organs.

---Striations are faint.---Involuntary in function.---Cells are uninucleate.---Fibres are cylindrical,

---Innervated by autonomic nervous system (not directly).

---Heart muscles.

24. Nitrogen fixation in Leguninous plants: ---In leguminous plants, nitrogen fixation is carried out by Rhizobium which lives as a symbiont in their root nodules.---The root nodule contains all the biochemical components necessary for nitrogen fixation.---During this process, a dinitrogen molecule is progressively refuced by the addition of pairs of hydrogen atoms, into two molecules of ammonia; the reaction is catalysed by the enzyme nitrogenase.---The enzyme is extremely sensitive to oxygen; to protect it from oxygen, the root nodules contain a pinkish pigment called leghaemoglobin, that acts as oxygen scavenger.---The process also requires the following:

i) a strong reducing agent like NADH/NADPH/FADH, to transfer hydrogen to dinitrogen.ii) energy in the form of ATP

---The overall rocess can be represented in the following equation:N2+8e-+8H++16ATP 2NH3+ H2+ 16ADP+ 16PI

Refer fig. to Ans.25, NCT(Delhi), 2007.

25. a) Respiratory quotient refers to the ratio between the volume of carbon dioxide evolved and the volume of oxygen consumed.

b) Coleoptile is the leaf-like sheath that covers and protects the plumule.c) Coleorhiza is the sheath that protects the radical.d) Bulliform cells control the rolling movement of leaves of monocot plants like

grasses.

26. Urine formation is mammals.---Urine formation involves three main processes; they are: i) Glomerular filtration (ii) Tubular reabsorption and (iii) Tubular secretion

i) Glomerular filtration

---A protein-free fluid is filtered from blood of glomerular capillaries into the lumen of Bowman’s capsule.

---The filtration is caused by the blood pressue in the glomerular capillaries.---Filtration occurs through three layers, which form the filtration membrane; they are:i) Endothelium of glomerular capillariesii) Epithelium of Bowman’s capsuleiii) Basement membrane between the two layers:---The epithelial cells or podocytes of the Bowman’s capsule are arranged in an intricate

manner, to leave some filtration slits.---The blood is filtered so finely that the composition of the filtrate is very similar to

plasma except for the plasma proteins.---The glomerular filtration rate is about 125 ml/min.

ii) Reabsorption---Nearly 90% of the filtrate is reabsorbed in the renal tubule of the epithelial cells of the

lining of renal tubule.---Certain substances like glucose, amino acids, Na+ ions, K+ions and calcium ions are

reabsorbed actively.---Water is reabsorbed passively by osmosis.---Certain other substances like CL- ions are absorbed passively.

iii) Tubular Secretation---It is the process by which certain substances /ions like K+ and ammonia are directly

secreted into the lumen of the nephron.---This step is important in urine formation, as it helps to maintain the ionic balance and

pH of the body fluids.OrDigestion of carbohydrates:---Carbohydrate digestion starts in the mouth.---30% of the starch is hydrolysed by ptyalin (salivary amylase) into maltose.---The action of salivary amylase is inhibited by hydrochloric acid in the stomach.---Digestion of starch continues in the intestine; the remaining 70% of the starch is hydrolysed by pancreatic amylase into maltose.---Maltose and other sugars are digested by the enzymes called disaccharidases of the intestinal juice(succusentericus).---Sucrose is acted upon by sucrose and broken into one molecule of glucose and one molecule of fructose.---Maltose is hydrolysed by maltase into two molecules of glucose.---Lactase acts upon the milk sugar, lactose, and brakes into one molecule of glucose and one molecule of galactose. The final products of carbohydrate digestion are monosaccharides like glucose, fructose and galactose.---The end products are actively absorbed.27. Biosynthetic phase of Photosynthesis:---It occurs in the stroma of chloroplasts.

---These reactions reduce the carbon dioxide into carbohydrates, making use of the ATP and NADPH2 produced in the photochemical reactions.---The reactions are also called as Calvin cycle.---The three phases of Calvin cycle are as follows:i) Carboxylation

---Six molecules of Ribulose 1, 5 bisphosphate react with six molecules of carbon dioxide to form six molecules of a short-lived 6C-compound.

---The reaction is catalysed by RuBPcarboxylase(Rubisco).---The six molecules of the ^C-intermediate break into 12 molecules of 3-

phosphoglyceric acid (3-PGA), a 3C-compound.---It is through this step that carbon dioxide is fixed in the plant.ii) Reduction---12 molecules of 3-phosphoglyceric acid are converted into 12 molecules of 1, 3

diphospho-glyceric acid, utilizing 12 molecules of ATP and then reduced to 3-phosphoglyceraldehyde making use of 12 molecules of NADPH.

iii) Regeneration of RuBP---10 molecules of phosphoglyceraladehyde, by a series of complex enzyme-catalysed

reactions, are converted into six molecules of Ribulose 1, 5-bisphosphate; six molecules of ATP are needed for this step.

---This step of regeneration of RuBP is important for the cycle to continue.---C4 plants do not show photorespiratory losses and hence are photosynthetically more

efficient.Refer fig. to Ans. 15 NCT (Delhi), 2007.OrKreb’s cycle: This process occurs in the mitochondrial matrix.Major steps:---Acetyl Co-A, formed by the oxidative decarboxylation of pyruvic acid enters the Kreb’s cycle.---It combines with oxalo acetic acid(OAA), a 4C-compound, to form a 6C-compound, citric acid;---Citrate is then isomerised into isocitrate.Refer fig. to Ans. 18 NCT (Delhi), 2007.---Isocitrate is converted into oxalosuccinic acid in the presence of NAD and isocitrate dehydrogenase.---Oxalosuccinic acid is then decarboxylated into a-ketoglutaricacid (a KG), in the presence of a decarboxylase enzyme.--- a-ketoglutaric acid is converted into succinyl Co-A in the presence of NAD, Co-A and enzyme a-ketoglutaric dehydrogenase.---When succinyl Co-A is converted into succinic acid, one molecule of GTP is formed and Co-A is released.---In the remaining part of the cycle, succinic acid is converted into OAA, so that the citric acid cycle can continue to operate.---During this cycle three molecules of NAD and one molecule of FAD are reduced to NADH and FADH respectively.---This cycle is called as citric acid cycle because the first product is citric acid.

Role of Citric acid cycle.a) This is the major pathway for the production of ATP molecules.b) Many intermediate compounds from the cycle are used in the synthesis of other

biomolecules like amino acids, chlorophyll, etc.28. a) Prophase I

It is divided into five stages: i) Leptotene:---Condensation and coiling of chromatin fibres lead to the formation of distinct

chromosomes.---The chromosomes appear as fine single threads of beads.---As they contract and become thicker, their dual nature becomes visible.ii) Zygotene:---The homologous chromosomes start pairing (synapsis).---It is accompanied by the formation of synaptonemal complex.---The chromosomes occur in the form of bivalents.iii) Pachytene:---The chromosomes continue to become shorter and thicker.---The two sister chromatids of each chromosome become visible and the bivalent

becomes a tetrad with four chromatids.---Recombination nodules appear and crossing over starts.iv) Diplotene:---Crossing over is completed.---The two homologous chromosomes start separating from each other except at the

sites of crossing over.---Chiasmata become visible.---The chromosomes continue to contract.v) Diakinesis:---The chiasmata move to the tip of the chromosomes and may step out from some or

remain at the tips.---The chromosomes are fully condensed.---The nucleolus and nuclear membrane disappear.---Spindle formation is initiated.

b) Differences:Spring wood Autumn wood---The wood formed during favourable growth season (spring and summer), is called spring wood.---The cambium is very active and the secondary xylem vessels are larger in dimension.--It is lighter in colour.---It has a lower density.

---The wood formed during unfavourable growth periods (winter and autumn), is called autumn wood.---The cambium is less active and the wood produced has vessels of narrow dimension.

---It is darker in colour.---It has a higher density.

c) Differences: Cytokinesis in Plant Cells Cytokinesis in Animal Cells--It starts with the formation of cell plate during telophase.

---The cell plate grows from the centre towards the lateral walls; so it is described as centrifugal.

--It starts as a constriction in the cellMembrane during late anaphase or early telophase.---The furrow deepens from the periphery towards the centre and meet at the centre; so it is described as centripetal.