Class 11 Question Paper 2023 Biology

ANNUAL EXAMINATION

Question Paper
2023

NCERT BASED SYLLABUS
FOR CBSE AND STATE BOARD
FOLLOWING NCERT

ANNUAL EXAMINATION (2022-23)

Class - XI Subject – Biology
Time – 3 Hours Maximum Marks - 70

General Instructions:
(i) All questions are compulsory.
(ii) The question paper has five sections and 33 questions. All questions are compulsory.
(iii) Section–A has 16 questions of 1 mark each; Section–B has 5 questions of 2 marks each;
Section– C has 7 questions of 3 marks each; Section– D has 2 case-based questions of 4 marks
each; and Section–E has 3 questions of 5 marks each.
(iv) There is no overall choice. However, internal choices have been provided in some
questions. A student has to attempt only one of the alternatives in such questions.
(v) Wherever necessary, neat and properly labeled diagrams should be drawn.

SECTION-A
1. The common characteristics between tomato and potato will be maximum at the level of their
a. Genus b. Family c. Order d. Division
2. Which one of the following conditions are favourable for formation of carbonamino
haemoglobin?
a. low pCO2 b. high pO2 c. low H+ d. low pO2
3. The diagram below shows ATP synthesis through chemiosmosis. Which option shows the
correct labelling of 1, 2, 3 and 4 in the diagram?

a. 1 - F1, 2 - Thylakoid membrane, 3 - Photosystem-I, 4 - Photosystem-II

b. 1 -F0, 2 - Thylakoid membrane, 3 - Photosystem-I, 4 - Photosystem-II
c. 1 - F1, 2 - Thylakoid membrane, 3 - Photosystem-II, 4 - Photosystem-I
d. 1 - F0, 2 - Thylakoid membrane, 3 - Photosystem-II, 4 - Photosystem-I

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4. After karyogamy followed by meiosis, spores are produced exogenously in
a. Neurospora b. Alternaria c. Agaricus d. Saccharomyces
5. The seedless vascular plants whose sporophyte is larger than their small independent
gametophyte
a. Pteridophyte b. Angiosperm c. Gymnosperm d. Thallophyte
6. In an inflorescence where flowers are borne laterally in an acropetal succession, the position of
the youngest floral bud shall be
a. Proximal b. Distal c. Intercalary d. Any where
7. Match the terms in column I with their description in column II and choose the correct option.
Column I Column II
A. IAA (i) Herring sperm DNA
B. ABA (ii) Bolting
C. Ehtylene (iii) Stomatal closure
D. GA (iv) Weed-free lawns
E. Cytokinin (v) Ripening of fruits
a. A – iv, B – iii, C – v, D – ii, E – i
b. A – v, B – iii, C – iv, D – ii, E – i
c. A – iv, B – i, C – v, D – iii, E – ii
d. A – v, B – iii, C – ii, D – i, E – iv
8. The following diagram represents a structure of chromosome. Identify the structures marked as
1,2 and 3.

a. 1 - Satellite, 2 - Primary constriction, 3 - Acrocentric
b. 1 - Satellite, 2 - Secondary constriction, 3 - Metacentric
c. 1 - Satellite, 2 - Centromere, 3 - Telocentric
d. 1 -Satellite, 2-Centromere, 3-Submetacentric
9. The following substances are the excretory products in animals. Choose the least toxic form
among them?
a. Urea b. Uric acid c. Ammonia d. Carbon dioxide
10. Many elements are found in living organisms either free or in the form of compounds. One of
the following is not, found in living organisms.
a. Silicon b. Magnesium c. Iron d. Sodium
11. Muscles with characteristic striations and involuntary are

a. Muscles in the wall of alimentary canal
b. Muscles of the heart
c. Muscles assisting locomotion
d. Muscles of the eyelids

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12. Which of the following disease is caused due to over secretion of the hormone from the
structure marked as X?

a. Gigantism
b. Diabetes mellitus
c. Diabetes insipidus
d. Grave's disease
Question No. 13 to 16 consist of two statements – Assertion (A) and Reason (R). Answer these
questions selecting the appropriate option given below:
A. Both A and R are true and R is the correct explanation of A.
B. Both A and R are true and R is not the correct explanation of A.
C. A is true but R is false.
D. A is False but R is true.
13. Assertion (A): Cold blooded animals do not have fat layer.
Reason (R): Cold blooded animals use their fat for metabolic process during hibernation.
14. Assertion (A): When a neuron is not conducting any impulse, i.e. resting, the axoplasm inside
the axon contains high concentration of Na+ and negatively charged proteins and low
concentration of K+.
Reason (R): In resting, the axonal membrane is comparatively more permeable to K +ions and
nearly impermeable to Na+ ions.

15. Assertion (A): During zygotene, chromosomes show bivalent stage.
Reason(R): Bivalent is half the number of chromosomes.
16. Assertion (A): Oxidation of one molecule of NADH produces to 3 molecules of ATP, and that
of one molecule of FADH2 produces 2 molecules of ATP.
Reason (R): The number of ATP molecules synthesised depends on the nature of the electron
donor.

SECTION-B
17. What is the significance of Juxta-glomerular apparatus (JGA) in kidney function?
18. What are the structural characteristics of
(a) Meristematic cells near root tip
(b) The cells in the elongation zone of the root
19. Differentiate between :
(a) Actinomorphic and Zygomorphic flower
(b) Racemose inflorescence and Cymose inflorescence

20. Mitosis results in the production of two cells, which are similar to each other. What would be
the consequence of each of the following irregularities that occur during mitosis?
(a) Nuclear membrane fails to disintegrate.
(b)Centromeres do not divide
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21. What are the constituents of the limbic system? Mention its functions.
(OR)
How does the transmission of a nerve impulse takes place across a chemical synapse?

SECTION-C
22. Trace the events in a muscle fibre from the time it receives the impulse up to the contractile
response.
23. Describe the process of Z scheme of light reaction.
24. (a) Name the following:
i. The green algae which is used as protein rich food by space travellers
ii. The gelatinous substance that covers the cell wall of phaeophyceae
iii. The reserve food in Porphyra
iv. The structure that fixes the brown algae to the substratum
(b) Gymnosperms are well adapted to withstand xerophytic conditions. Justify
25. What are the steps in the sexual cycle in kingdom fungi?
26. Explain the mechanism of the action of a protein hormone in human body.
(OR)
Name the hormones, their source glands and their mode of functioning to achieve calcium
homeostasis in the human body.
27. Mention the role of the following in a prokaryotic cell:
(a) Mesosome
(b) Chromatophores
(c) Gas vacuoles
28. Describe the components of the diffusion membrane of human respiratory system.

SECTION-D
29. Lipids are hydrocarbon containing molecules that make up the building blocks of living world.
These are small molecular weight compounds that are found in the insoluble fraction along
with polymeric substances. Lipids are soluble in nonpolar organic solvents and generally
insoluble in water. Lipids exist in various forms and there is great structural variety among
these forms. Different types of lipids include fatty acids, steroids, terpenes, phospholipids,
waxes, fats, etc. Lipids are hydrophobic and amphipathic in nature.
(a) Why do oils generally remain in liquid state even in winters?
(b) Why do physicians recommend vegetable oils rich in polyunsaturated fat for persons
suffering from cardiovascular diseases ?
(c) Why do fats release more energy than carbohydrates on oxidation?
(OR)
(c) Phospholipids form a thin layer on the surface of an aqueous medium. Justify.
30. Annelida (L - annulus - ring) is a diverse taxon of segmented worms. The phylum Annelida
includes soft bodied, elongated, bilaterally symmetrical, metamerically segmented coelomate
worms previously it was included under the phylum vermes by Linnaeus (1736).

The unique characteristic of the phylum Annelida is metamerism. The body is divided into a
number of similar parts. Each division or part of the body is known as somite or segments or
metameres. The metameres are arranged in a linear series. Externally the metameres are
differentiated by ring like grooves called the annuli. The internal segmentation is also complete

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and distinct and hence the coelom is divided by transverse septa. The phylum includes about
12000 described species.

(a) Name the structure present in phylum Annelida for osmoregulation and excretion?
(b) How do annelids locomote?
(c) You are given Leech, Nereis, prawn and scorpion. All of them have a segmented body
organisation. Will you classify them in one group? If no, state the important characters
based on which you will separate these animals into different groups.
(OR)
(c) Both Earthworm and roundworm are worm like organisms. How are they different from
each other?

SECTION-E
31. Describe the male reproductive system of the frog with labelled sketch.
(OR)
Give the possible reason for the following statements:
(a) A transparent nictitating membrane is present in the eyes of a frog.
(b) The first finger of the male frog is swollen.
(c) The skin of the frog is moist and slippery.
(d) Webs are present between the toes of frog.
(e) Frog is useful to mankind.
32. Explain the biosynthetic pathway of carbon dioxide fixation in chloroplast of green plants.
(OR)
What is glycolysis ? Where does glycolysis takes place in a cell ? Give an brief account on
glycolysis.

33. (a) Describe the events that occur during a cardiac cycle.
(b) Why is the human heart called myogenic?
(c) What do the P-wave and T-wave represent in the ECG?
(OR)
Read the passage given below and answer the following questions given:

Kidneys are the chief excretory organs and are mainly concerned with the excretion of urea in the
form of urine. They play a central role in cardiovascular homeostasis by ensuring a balance
between the fluid taken in and that is lost and excreted during everyday activities. This ensures
stability of extracellular fluid volume and maintenance of normal levels of blood pressure. Renal
fluid handling is controlled via neural and hormonal influences, with the former determining a
rapid dynamic response to changing intake of sodium whereas the latter cause a slower longer -
term modulation of sodium and water handling.
The function of our kidney is monitored and regulated by the feedback mechanisms which
involves the hypothalamus, juxta glomerular apparatus (JGA), and the heart.

(a)Name the hormone released by the heart for regulation of the kidney function.
(b)How does Anti Diuretic Hormone (ADH) regulate body fluid volume?
(c) Give the name of two actively transported substances in glomerular filtrate.

(d) State why the composition of glomerular filtrate is not the same as urine.

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