SAMPLE QUESTION—X1
TIME-3Hrs
INSTRUCTION: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.
MAX-MARKS---70
SECTION-A
Q1-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-B
Q9-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-C
Q19-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-D
Q28Name the intermediate compound of glycolysis and TCA cycle.
Draw the citric acid cycle.
OR
Q29-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 SCHEME
1-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=2
10-Any two difference
1x2=2
11-Labelled diagram( any four labeling)
1/2x4=2
12-Any two points
1x2=2
13-Any two difference
1x2=2
14-An inactive stage in cell cycle. OR any correct definition (2)
15-Any two points
1x2=2
16-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 formsIn 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)
OR
EMP pathway (1)
Steps involved
(4)
30-Taenia solium--------------------Taeniasis
Ascaris ---------------------------Ascariasis
Wuchereria-----------------------------Filariasis
Entamoeba------------------------------Amoebiasis
Plasmodium-------------------------Malaria
OR
Arthropoda
(1)
Four unique features
(2)
Any two importance
(2).
Dr. Binod Kumar, PGT(Bio), K.V. No.1, Bokaro
BLUE PRINT
SUB: BIOLOGY
CLASS – 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 PAPER
SUB: BIOLOGY
CLASS – XI
Time: 3 Hours
MM: 70 Marks
General Instructions:
(i)
(ii)
(iii)
(iv)
1.
2.
3.
4.
5.
6.
7.
8.
All questions are compulsory.
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.
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.
Wherever necessary the diagrams drawn should be neat and properly labeled.
SECTION A
Identify the correct scientific name of mango:
1
a) Mangifera Indica
b) Mangifera indica
c) mangifera indica
d) mangifera Indica
Name the specialized cells of blue green algae which are concerned with nitrogen
fixation
1
Give the scientific term for a flower which can be divided into two equal halves in any
radial plane passing through the centre.
1
Name the type of epithelium which is found in ducts of gland.
1
Identify the type of ribosome found in prokaryotes:
1
a) 80S
b) 90S
c) 70S
d) 60S
What do you mean by quiescent stage of the cell cycle?
1
Mention the reaction centre of PS I and PS II.
1
Name the structure of tracts of nerve fibres which connects two cerebral hemispheres.
1
SECTION B
9. Give four important characteristics of pteridophytes.
2
10. What is an exarch vascular bundle? In which part of the plant body it is found? 2
11. What is typhlosole? Write its function.
2
12. Distinguish between gram +ve and gram –ve bacteria.
2
13. What do you mean by water potential? Mention the factors which determine water
potential.
2
14. 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 Scheme
Biology
Class XI
M.M.70
SECTION A
1. b) Mangifera indica
2. Bulliform cells
3. Actinomorphic
4. Cuboidal epithelium
5. c) 70S
7. PSI-P700
PSII-P680
8. Corpus Callosum
1
1
1
1
1
½
½
1
SECTION B
9. Each character
10. Definition
Root
11. Definition
Function
12. Each difference
½x4=2
1
1
1
1
½x4=2
13. Definition
2Factors
14.a) Chlorine
b) Potassium
c) Iron
d)Zinc
15. Definition
Value
16. For Diphyodont teeth
Dental formula
17. Each difference
18. Expansion
Definition
Value
1
1
½
½
½
½
1
1
1
1
½x4=2
½
½
1
SECTION C
19. Definition
Differentiation
Example
20. Floral formula
Floral Diagram
1
1
1
1
2
21. Type of mouth
1
Mouth Parts
22. For each structure
23. Equational division
Significance
24. For each difference
25. Definition
Differentiation
26 Definition
Each difference
27. For each labeling
2
1x3=3
1
2
1x3=3
1
2
1
½x4=2
½x6=3
SECTION D
29.Definition
Glycolytic Pathway
Explanation
30. Definition
Diagram
Explanation
OR
Diagram
Explanation
1
2
2
1
2
2
2
3
Blue print
unit
1
DIVERSITY IN
LIVING WORLD
2
STUCTURAL
ORGANISATIO
N IN
PLANTS&ANIM
ALS
CELL:
STRUCTURE
&FUNCTION
Plant physiology
3
4
5
VSA
SA
1
2
MARK MARKS
S
1(1)
2(3)
SA1
3
MARKS
LA
5
MARKS
TOTAL
-
-
7(4)
-
2(2)
3(1)
5(1)
12(4)
4(1)
2(1)
3(3)
-
15(8)
-
2(2)
3(3)
5(1)
18(6)
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 XI
Subject-Biology
Section A
1. The bond linking two amino acids in protein.
1
2. a) Pivot joint
b) Cartilaginous joint/slightly movable joint.
½
½
3. Many ribosomes attached to mRNA.
1
4.i) Maintains total blood volume.
ii) Carries protein and lipid macromolecules to blood for circulation.
½
5. Adenine, Guanine.
6. As L.V sends blood to distant body parts.
7. They have a different cell wall structure.
½
½+ ½ =1
1
1
8. Which cell undergoes meiosis?
1
Section B
9. Estrogen-follicular cells of ovarian follicle.
Progesteron –corpus luteum.
1
1
10.a-Robert Brown
b-schleindon and schwann.
c-fluid mosaic model of cell membrane.
d-golgi apparatus.
11)correct reasons.
12)correct diagram and labelling.
13)carboxylaseRuBP+CO
OxygenaseRuBP +O2
½X4=2
1+1=2
1+1=2
2X3 PGA
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.
Two functions
1
1/2X2=1
Section C
19)correct explanation of mono,di, triglycerides
20)correct drawing and labeling of 6 parts.
1x3=3
1/2X6=3
21)correct description of primary, secondary and tertiary structure. 1X3=3
22 i)mitoticanaphase,anaphase 1 of meiosis 11
ii)correct points of difference.
1
iii)correct number of chromosomes
1/2+1/2=1
23)correct definition of each of three.
24)correctexplaination of the each.
1X3=3
1+1/2x2=3
25)yes it will carry out photosynthesis
1
Two important functions of other pigments
26)Terrestrial amphibians, Marine fishes
Two correct point of differences
27) Drawing and description of three types of neuron
1+1=2
½+1/2=1
1+1=2
1+1+1=3
Section-D
28)a) Auxin
b) Ethylene
c) Cytokinine
d) ABA
e) GA3
1x5=5
OR
Correct definition
3 categories of Plants
Name of hormone
29.
1
1X3=3
1
Correct description of digestion of Carbohydrates
Correct answer of end product absorption
3
2
OR
30.
i.
ii.
iii.
iv.
v.
Correct diagram and labeling of the parts
1/2X10=5
Metaphase
Anaphase
Zygoleni of prophase I
Pachytene
G2 Phase
1X5=5
OR
Correct diagram & labeling of 5 substages of Prophase 1
1/2x10=5
Sample Question Paper
Class : XI
Marks : 70
Max.
Sub : Biology
Hours
Time : 3
General Instructions :
(i)
(ii)
(iii)
All questions are compulsory.
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.
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
B
Nucleus
Cell theory
Singer & Nicholson
Camillo Golgi
C
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 – C
19. 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)
(ii)
(iii)
Name the type of cell division and its phase shown in diagram (a) & (b)
Distinguish between these two phases of cell division.
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) Hypotonic
24. 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 twig
b) Quick ripening of a fruit
c) Delay in leaf senescence
d) 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
1 2 3
U
5 1 2
I
Diversity in living World
1
II
Structural organization in Animals and
plants
1
III
cell structure and Function
2 3
5
IV
Plant Physiology
2
5 1
V
Human Physiology
2 3
A
3
1 2
1
2
3
%
1
7
1
12
3
3
2
15
2 3
3 5
2 6 9 10 2 8 12 5 1 2 6
total
TOTAL
3 5 1 2 3 5 1 2 3 5
2
3
S
2
18
1 2
18
3 4
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 following
a) 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+energy
Q12 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.
B.
C.
D.
Quickly ripen a fruit.
Promote nutrient mobilization.
Induce immediate stomatal closure.
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 roots
a) Banyan tree-prop roots
b) Mangrove tree- pneumatophores
.A 2 gas 1 –O2 and gas 2-CO2 ½ mark
½ mark
½ mark
Process- diffusion
½ mark
A3
Responsible for production of methane (biogas).
A4
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.
F.
G.
H.
Quickly ripen a fruit.- Ethylene
Promote nutrient mobilization.- cytokinin
Induce immediate stomata closure. -ABA
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.
e) Diabetes mellitus.
–Growth hormone
- Insulin
f) 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
c) glycosidic,
d) peptide
illustration: ½ mark
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
(3mark),
secretion.
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-BIOLOGY
A.Unit wise distribution of marks :
Unit-1:Diversity in the living world
07
Unit-2:Structural organization in plants & animals
12
Unit-3:Cell structure & function
15
Unit-4:Plant physiology
18
Unit-5:Animal physiology
18
B.Types of questions :
Knowledge
Understanding
Application
1x4ques,
2x6ques.,3x5ques,
5x1ques
No. of ques-16
Marks-36
Skill
1x2ques,
1x2ques,
2x1ques,3x2ques,5x1que, 2x3ques,
3x1ques,5x1ques
No. of ques-06
No. of ques-07
Marks-15
Marks-16
C.Number of questions :
Sl
Form of question
Marks for
no.
each ques.
1.
Very short answer (VSA) 01
2.
Short answer (SA-I)
02
3.
Short answer (SA-I
03
4.
Long answer (LA)
05
TOTAL
D.Unit-wise distribution of marks :
Types of ques.
Units
Diversity in the living world
Structural organization in plants & animals
Cell: Structure & functions
Plant physiology
Animal physiology
Total
No. of ques.
Marks
08
10
09
03
30
08
20
27
15
70
VSA
1 marks
2 (2)
-3 (3)
2 (2)
1 (1)
8 (8)
SA-I
2 marks
1 (2)
2 (4)
3(6)
1 (2)
3 (6)
10 (20)
No. Total
of
marks
ques
Total
no.ofques
=30
Total marks
=70
3x1que
No. ofques01
Marks-03
SA-II
3marks
1 (3)
1 (3)
2 (6)
3 (9)
2 (6)
9 (27)
LA
5 marks
-1 (5)
-1 (5)
1 (5)
3 (15)
Total
07
12
15
18
18
70
Marking scheme of Q.P. of Class-XI
Section-A
1.Cell gets swollen/turgid.
1
2.Temp. ,light, humidity, windspeed.
(anytwo)
1
3.Pleuro Pneumonia Like Organisms.
1
4.Ability to emit light
1
5.Cells that don’t divide enter an inactive stage called quiescent stage(Go). 1
6.ABA/Abscisic acid.
1
7.One mol.
1
8.No rods or cones are present.
1
Section-B
9.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=1
15.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-C
19.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-D
28.Correct description & mechanism to be given.
3+2=(5)
Or
Lens shaped openings in the bark of trees ; function- gaseous exchange.
Differences – any three points.
2+3=(5)
29.Correct description of ETS.
Or
TCA cycle to be given with energy calculation.
(5)
30.Three steps of urine formation to be given and explained.
Or
Resting membrane potential, depolarization, repolarization to be explained.
(5)
CLASS – XI
Sub.: Biology
Time : 3 Hrs
F.M.: 70
General Instructions:i.
ii.
iii.
iv.
All questions are compulsory.
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.
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.
Whenever necessary, supplement your answer with diagram.
Section: A
1.
2.
3.
4.
5.
6.
7.
What will happen to a cell when it is placed in higher water potential?
(1)
Name the factors which effect the rate of transpiration.
(1)
Expand PPLO.
(1)
What is bioluminescence?
(1)
What is G0 phase?
(1)
Name the hormone that makes the plants more tolerant to various stresses.
(1)
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.
11. Why are lipids included under macro molecules?
12. What are mesosomes?Write two functions of mesosomes.
13. What are co-factors? Describe one co-factor with reference to enzymes.
14. i) Mention two functions of cytokinins.
ii)Name two synthetics Auxins.
15. What is R.Q.?Show with an equation that RQ is one for carbohydrate.
16. What is ADH? What is its role in forming hypertonic Urine?
17. Where is pneumotoxic center located? How is regulate respiratory rate?
18. What role does kidney and lungs play in excretion?
(2)
(2)
(1+1=2)
(1+1=2)
(1+1=2)
(1+1=2)
(2)
(2)
(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: D
28. 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.
OR
How is nerve impulse transmitted along a mylelinated nerve fibre.
----000-----
(5)
BLUEPRINT OF Q.P. OF CLASS XI-BIOLOGY
A.Unit wise distribution of marks :
Unit-1:Diversity in the living world
Unit-2:Structural organization in plants & animals
Unit-3:Cell structure & function
Unit-4:Plant physiology
Unit-5:Animal physiology
B.Types of questions :
07
12
15
18
18
Knowledge
Understanding
Application
Skill
1x4ques,
2x6ques.,3x5ques,
5x1ques
No. of ques-16
Marks-36
1x2ques,
1x2ques,
3x1que
2x1ques,3x2ques,5x1que, 2x3ques,
3x1ques,5x1ques
No. of ques-06
No. of ques-07
No.
Marks-15
Marks-16
ofques01
Marks03
No. Total
of
marks
ques
Total
no.ofques
=30
Total marks
=70
C.Number of questions :
Sl Form of question
Marks for
no.
each ques.
1. Very short answer
01
(VSA)
2. Short answer (SA-I)
02
3. Short answer (SA-I
03
4. Long answer (LA)
05
TOTAL
D.Unit-wise distribution of marks :
Types of ques.
Units
Diversity in the living world
Structural organization in plants &
animals
Cell: Structure & functions
Plant physiology
Animal physiology
Total
No. of
ques.
08
Marks
10
09
03
30
20
27
15
70
08
VSA
1
marks
2 (2)
--
SA-I
2
marks
1 (2)
2 (4)
SA-II
LA
3marks 5
marks
1 (3)
-1 (3)
1 (5)
Total
3 (3)
2 (2)
1 (1)
8 (8)
3(6)
1 (2)
3 (6)
10 (20)
2 (6)
3 (9)
2 (6)
9 (27)
15
18
18
70
-1 (5)
1 (5)
3 (15)
07
12
BIOLOGY QUESTION PAPER CLASS11
KENDRIYA VIDYALAYA NO.2 SALTLAKE KOLKATA.
Subject – Biology
Class - XI
Time : 3 hours Max.Marks 70
General Instructions:
1.
2.
All questions are compulsory.
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 of
5 marks weightage . Attempt only one of the choices in such questions.
4.
Wherever necessary, the diagrams drawn should be neat and properly labelled.
SECTION A
Q.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 B
Q6 How are heart sounds produced during cardiac cycle?
Q7 what is meant by apoplastpathway?why does it occur in cortex & not in endodermis
Q8 Differenciate between dicot &moncot root.
Q9 Name the end products of Aerobic & Anaerobic glycolysis
Q10. How areAscomycetes different from basidiomycetes
Q11 How many cells are present in the egg apparatus of plant.
Q12 What are the functions of golgi bodies
Q13 Give difference between Anaphase1 & anaphase 2
Q14 Describe Gout
Or
Name the source & function of ADH
Q15. 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.
Or
a) 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.
Or
Describe 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?
Or
Draw 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?
Answers
1. 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.
---Vascular bundles are conjoint and collateral.
---Xylem is endarch.
---Xylem is exarch.
---Vascular bundles are open, i.e., cambium is ---Vascular bundles are closed, i.e., cambium is
present.
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
---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.
Basidiomycetes
---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)
‘S’ phase
---In this substage of interphase, there
is replication of DNA; the amount of
DNA in a cell
Anaphase
I becomes doubled.
---The centromeres do not divide and
os one whole chromosome moves to
the pole.
‘G1’ phase
---It is the first substage of
interphase, where there is synthesis
of RNAs and
Anaphase
II proteins.
---The centromere divides, and one
half of a chromosome moves to one
pole, while the other half moves to
the opposite pole.
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:
Rods
---These are more sensitive to light
are meant for vision in dim
light(scotopic vision).
Cones
---These are meant for vision in
bright light(photopic vision).
---They have the ability to make
---They do not have the ability to
make coloured image.
---These contain the visual pigment
rhodopsin.
coloured image.
---These contain the pigment
iodopsin.
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 Action
A 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) PhylumActhropoda
c) Phylum Annelida
d) Phylum Echinodermata
e) Phylum Mollusca
f) 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.
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. Leucocytes
Granulocytes(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
%
Or
a) Phyllotaxy refers to the mode of arrangement of leaves on a stem/branch.
---In China Rose, phyllotaxy in alternate.
b) Differences:
Racemose 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.
c) Cucurbita and Vitis.
Cymose Inflorescence
---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.
23. Three types of muscular tissues:
Skeletal / Striated muscles
Smooth / Non- striated
muscles
i) Striations are prominent.
---Striations are absent.
ii) Voluntary in function.
---Involuntary in function.
iii) Cells are multinucleate.
---Cells are uninucleate.
iv) Fibres are cylindrical and
---Fibres are spindle shaped.
unbranched.
Branched and show
intercalated discs.
v) Innervated by voluntary
---Innervated by autonomic
nervous system.
nervous system.
e.g., Muscles of limbs.
---Muscles of visceral organs.
Cardiac muscles
---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 capillaries
ii) Epithelium of Bowman’s capsule
iii) 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.
Or
Digestion 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 3phosphoglyceric 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 3phosphoglyceraldehyde 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.
Or
Kreb’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 ---The wood formed during unfavourable
season (spring and summer), is called spring
growth periods (winter and autumn), is called
wood.
autumn wood.
---The cambium is very active and the
---The cambium is less active and the wood
secondary xylem vessels are larger in
produced has vessels of narrow dimension.
dimension.
--It is lighter in colour.
---It is darker in colour.
---It has a lower density.
---It has a higher density.
c) Differences:
Cytokinesis in Plant 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.
Cytokinesis in Animal Cells
--It starts as a constriction in the cell
Membrane 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.