Questions
Solutions
Annual Exam - 2024
Code: 57/2/2 (set-2)
I. Please check that this question paper contains 23 printed pages.
II. Please check that this question paper contains 33 questions.
III. Q.P. Code given on the right hand side of the question paper should be written on the title
page of the answer-book by the candidate.
IV. Please write down the serial number of the question in the answer-book before
attempting it.
V. 15 minute time has been allotted to read this question paper. The question paper will be
distributed at 10.15 a.m. From 10.15 a.m. to 10.30 a.m., the students will read the
question paper only and will not write any answer on the answer-book during this period.
BIOLOGY (Theory)
Time allowed:3 hours
Maximum Marks:70
General Instructions :
Read the following instructions carefully and follow them:
i. This question paper contains 33 questions. All questions are compulsory.
ii. Question paper is divided into five sections - Sections A, B, C, D and E.
iii. Section A - questions number 1 to 16 are multiple choice type questions. Each question
carries 1 mark.
iv. Section B - questions number 17 to 21 are very short answer type questions. Each
question carries 2 marks.
v. Section C - questions number 22 to 28 are short answer type questions. Each question
carries 3 marks.
vi. Section D - questions number 29 and 30 are case-based questions. Each question
carries 4 marks. Each question has subparts with internal choice in one of the subparts.
vii. Section E - questions number 31 to 33 are long answer type questions. Each question
carries 5 marks.
viii. There is no overall choice. However, an internal choice has been provided in Sections B,
C and D of the question paper. A candidate has to write answer for only one of the
alternatives in such questions.
ix. Kindly note that there is a separate question paper for Visually Impaired candidates.
x. Wherever necessary, neat and properly labelled diagrams should be drawn.
SECTION A
Questions no. 1 to 16 are Multiple Choice Type Questions, carrying 1 mark each.
(16×1=16)
1. Homologous organs indicate:
a. Convergent evolution
b. Adaptive Radiation
c. Divergent Evolution
d. Natural selection
2. A population is in genetic equilibrium/Hardy-Weinberg equilibrium for a gene with 2
alleles (dominant allele is A and recessive allele a). If the frequency of allele A is 0.6,
then the frequency of genotype Aa is:
a. 0.21
b. 0.42
c. 0.48
d. 0.32
3. In the double helical structure of DNA molecule, the strands are:
a. identical and complementary
b. identical and non-complementary
c. anti-parallel and complementary
d. anti-parallel and non-complementary
4. In a transcription unit the terminator is located towards the:
a. 3' end of the template strand
b. 5' end of the template strand
c. 5' end of the coding strand
d. 3' end of the coding strand
5. Which one of the following option denotes mating between relatives in human pedigree
analysis
a.
b.
c.
d.
6. The vector for dengue fever is:
a. Female Aedes mosquito
b. Female Anopheles mosquito
c. Male Aedes mosquito
d. Female Culex mosquito
7 Which one of the following pairs is not correctly matched?
.
(A) Clostridium butylicum Butyric acid
(B) Trichoderma polysporum Cyclosporin A
(C) Monascus purpureus Citric Acid
(D) Streptococcus Streptokinase
a. Pair (A) is not correct.
b. Pair (B) is not correct.
c. Pair (C) is not correct.
d. Pair (D) is not correct.
8. Which of the following is not required for PCR?
a. Restriction endonuclease
b. Taq Polymerase
c. Primer
d. DNA segment
9. The pyramid of biomass in sea is generally inverted because in sea:
a. Biomass of fishes exceeds that of phytoplankton.
b. Number of phytoplanktons is more.
c. Number of phytoplanktons is less.
d. Large fishes feed on small fishes.
10. In humans, the secondary oocyte completes meiotic division when:
a. it gets implanted in the uterine endometrium.
b. it is released from the matured Graafian follicle.
c. it is penetrated by the sperm cell.
d. acrosomal enzymes break down the zona pellucida.
11 Match the items in Column I with those in Column II and select the correctly matched option
. from those given below:
Column I Column II
Cross Phenotypic Ratio
(a) Mendelian monohybrid (i) 1 : 2 : 1 (F2)
(b) Mendelian dihybrid (ii) 1 : 1
(c) Incomplete dominance (iii) 3 : 1 (F2)
(d) Test cross (monohybrid) (iv) 9 : 3 : 3 : 1 (F2)
a. (a) - (ii), (b) - (iv), (c) - (i), (d) - (iii)
b. (a) - (iii), (b) - (i), (c) - (iv), (d) - (ii)
c. (a) - (iii), (b) - (iv), (c) - (i), (d) - (ii)
d. (a) - (ii), (b) - (i), (c) - (iv), (d) - (iii)
12. The functional megaspore of an angiosperm develops into:
a. Embryo sac
b. Endosperm
c. Embryo
d. Ovule
For Questions number 13 to 16, two statements are given - one labelled as Assertion
(A) and the other labelled as Reason (R). Select the correct answer to these questions
from the codes (A), (B), (C) and (D) as given below.
A. Both Assertion (A) and Reason (R) are true and Reason (R) is the correct
explanation of the Assertion (A).
B. Both Assertion (A) and Reason (R) are true, but Reason (R) is not the correct
explanation of the Assertion (A).
C. Assertion (A) is true, but Reason (R) is false.
D. Assertion (A) is false, but Reason (R) is true.
13. Assertion (A): Loss of biodiversity can occur due to overexploitation of resources.
Reason (R): Introduction of Clarias gariepinus in Indian rivers has led to a decline in
native Indian fishes.
a. Both A and R are true and R is the correct explanation of A.
b. Both A and R are true but R is not the correct explanation of A.
c. A is true but R is false.
d. A is false but R is true.
14. Assertion (A): In genetic engineering, antibiotic genes are used as selectable markers.
Reason (R): Selectable markers help us to identify transformants from non-
transformants.
a. Both A and R are true and R is the correct explanation of A.
b. Both A and R are true but R is not the correct explanation of A.
c. A is true but R is false.
d. A is false but R is true.
15. Assertion (A): Virus-infected cells produce interferons.
Reason (R): Interferons can cause inflammation of virus-infected cells.
a. Both A and R are true and R is the correct explanation of A.
b. Both A and R are true but R is not the correct explanation of A.
c. A is true but R is false.
d. A is false but R is true.
16. Assertion (A): RNA is unstable and can mutate at a faster rate.
Reason (R): The presence of 2' - OH group in every nucleotide of RNA makes it labile
and easily degradable.
a. Both A and R are true and R is the correct explanation of A.
b. Both A and R are true but R is not the correct explanation of A.
c. A is true but R is false.
d. A is false but R is true.
SECTION B
17. How is the rate of decomposition affected by the nature of detritus and temperature? 2
18. How is a restriction endonuclease named? Explain with the help of a suitable example. 2
19. (i) Name any two copper-releasing intra-uterine devices. State two reasons that make 2
them effective contraceptives.
OR
(ii) Name any two outbreeding devices that flowering plants have developed and 2
explain how they help in encouraging cross-pollination.
20. Although Haemophilia and sickle cell anemia are two blood related Mendelian 2
disorders, yet, they differ in their pattern of inheritance. State any two differences.
21 Identify A, B, C and D in the following table: 2
.
Scientific name of the plant Drug Effect on the human body/human system
(a) Papaver somniferum A Depressant/slows down body function
(b) Cannabis sativa Cannabinoids B
(c) Erythroxylum coca C D
SECTION C
22. Predation is referred to as a detrimental interaction. Explain any three positive roles, 3
supported by an example each, that a predator plays in an ecosystem.
23. Given below is a pie chart representing global diversity of vertebrates. 3
a. Redraw the pie chart identifying the groups and in their respective positions.
b. Mention two examples of recently extinct animals.
24. a. Differentiate between humoral immune response and cell-mediated immune 3
response.
b. Draw a schematic diagram of an antibody molecule and label any four parts.
25. (i) Explain the mechanism of haplo-diploid pattern of sex determination with the 3
help of a suitable example. Why is this pattern so called?
OR
(ii) T.S. Morgan and his colleagues worked with Drosophila melanogaster for their 3
experiments. State the findings they arrived at and explain how.
26. Human blood group (ABO group) inheritance is a good example of multiple allelism 3
and co-dominance. Justify the statement.
27. a. Why is in vitro fertilization (IVF) so named? State its importance. 3
b. Distinguish between GIFT and ZIFT.
28. The diagram given below is a biomolecule needed for sugar metabolism in human 3
beings.
a. Name this biomolecule and mention whether it is in an active state or inactive
state.
b. Identify the parts marked as A, B, C and D.
SECTION D
Questions No. 29 and 30 are case-based questions. Each question has 3 sub-questions
with internal choice in one sub-question.
29. Read the following passage and answer the questions that follow. 4
In 1981, the health workers of United States of America had become aware of the
increased frequency of Kaposi's sarcoma, cancer of the skin and blood vessels and
another disease pneumocystis pneumonia, a respiratory infection caused by a
protozoan. Both these diseases were very rare in the general population, but occurred
frequently in more severely "immunosuppressed" individuals. This led to the
recognition of the immune system disorder that was named Acquired Immune
Deficiency Syndrome (AIDS).
In 1983, virologists working in the USA and France had identified a causative agent for
'AIDS', now known as Human Immunodeficiency Virus (HIV). 'HIV' follows a set path
to attack the human body to cause the disease.
a. Name the group of cells the HIV attacks after gaining entry into the human
body and write the various events that occur within this cell. (1)
b. Write the expanded form of the diagnostic test used for detecting AIDS. Write
the possible treatment available for the disease at present. (1)
c. Mention any two steps suggested by WHO for preventing the spread of this
disease. (2)
OR
"A patient suffering from AIDS does not die of this disease but from some other
infection." Justify the statement. (2)
30. Read the following passage and answer the questions that follow. 4
Spermatogenesis is an important primary sex characteristic in humans and all other
vertebrates. The process is coordinated and controlled under the influence of hormones.
It starts with the onset of puberty in humans and thereafter continues. The primordial
cells within the embryonic testis which differentiate into spermatogonia are the
precursors of the sperms. These are located at the outer walls of the seminiferous
tubules where the process of spermatogenesis proceeds.
a. State the site of action of FSH in the testes and describe its action thereafter. (2)
OR
Describe the role of LH in the process of spermatogenesis. (2)
b. Name the cells and their products which undergo: (1)
i. Mitosis and Differentiation
ii. Meiosis I and Meiosis II
during the process of spermatogenesis.
c. Name the accessory ducts that the sperms travel through from seminiferous
tubules to reach the epididymis. (1)
SECTION E
31. (i) i. Why should a cell be made competent to take up an alien DNA? How can 5
a bacterial cell be made competent using calcium ions? Explain.
ii.
1. State the importance of gel electrophoresis in biotechnology.
2. Explain the principle on which this technique works.
3. Mention why ethidium bromide is used in this technique.
OR
(ii) Bt cotton, the genetically modified crop, has greatly helped the cotton farmers to 5
increase their crop yield.
i. How was Bt cotton plant made resistant to bollworm? Explain.
ii. Describe the mechanism that leads to the death of bollworms feeding on
Bt cotton plants.
32. (i) i. Explain the process of double fertilization in an angiosperm starting from 5
the germination of pollen grains on the stigma, mentioning the ploidy of
the end products formed at the end. State the role of synergids during the
course of the process.
ii. Why does the development of endosperm precede that of the embryo?
OR
(ii) i. Mention the site where fertilisation of the ovum occurs in a human female. 5
Explain the process of fertilization and mention how polyspermy is
prevented
ii. Name the embryonic stage that gets implanted in the uterus. Explain the
process of implantation in a human female.
33. (i) i. State Mendel's law of independent assortment. 5
ii. Explain this law by taking the example of a cross between two
heterozygous parents of pea plants with respect to flower colour and
flower position using Punnett Square.
OR
(ii) Explain Griffith's experiment conducted in search of genetic material and write 5
the conclusion he arrived at. How did Avery, MacLeod and McCarty establish the
biochemical nature of the "Genetic Material" identified by Griffith?
