SECTION – A
Question Nos. 1 to 16 are Multiple Choice type Questions, carrying 1 mark
each. 16 1 = 16
1. A person with trisomy of 21st chromosome shows 1
(i) Furrowed tongue (ii) Characteristic palm crease
(iii) Rudimentary ovaries (iv) Gynaecomastia
Select the correct option, from the choices given below :
(A) (ii) and (iv) (B) (i), (ii) and (iv)
(C) (ii) and (iii) (D) (i) and (ii)
2. Which one of the following chromosomal event will not result in genetic
variation amongst the offsprings ? 1
(A) Independent assortment (B) Crossing over
(C) Linkage (D) Mutation
3. Identify the correct labellings in the figure of a fertilised embryo sac of an
angiosperm given below : 1
(A) A – zygote, B – degenerating synergids, C – degenerating antipodals,
D – PEN
(B) A – degenerating synergids, B – zygote, C – PEN, D – degenerating
antipodals
(C) A – degenerating antipodals, B – PEN, C – degenerating synergids,
D – zygote
(D) A – degenerating synergids, B – zygote, C – degenerating antipodals,
D – PEN
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4. Study the pedigree chart of a family showing the inheritance pattern of a
certain disorder. Select the option that correctly identifies the nature of the
trait depicted in the pedigree chart. 1
(A) Dominant X-linked
(B) Recessive X-linked
(C) Autosomal dominant
(D) Autosomal recessive
5. Which one of the following statements is correct in the context of observing
DNA separation by agarose gel electrophoresis ? 1
(A) DNA can be seen in visible light.
(B) DNA can be seen without staining in visible light.
(C) Ethidium bromide stained DNA can be seen in visible light
(D) Ethidium bromide stained DNA can be seen under UV light.
6. A phenomenon where a male insect mistakenly identified the patterns of a
orchid flower as the female insect partner, and tries to copulate and thereby
pollinates the flower is said to be : 1
(A) Pseudocopulation (B) Pseudopollination
(C) Pseudoparthenocarpy (D) Pseudofertilisation
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7. Observe the schematic representation of assisted reproductive technology
given below : 1
Identify the most appropriate technique depicted in the above diagram.
(A) IUT (B) IUI
(C) ICSI (D) ZIFT
8. The source of ‘Smack’ is : 1
(A) Leaves of Cannabis sativa
(B) Flowers of Datura
(C) Fruits of Erythroxylum coca
(D) Latex of Papaver somniferum
9. The first antibiotic was discovered accidentally by A while working on B. ‘A’
and ‘B’ are 1
(A) A – Waksman; B – Streptococcus
(B) A – Fleming; B – Penicillium notatum
(C) A – Waksman; B – Bacillus brevis
(D) A – Fleming; B – Staphylococci
10. If the sequence of nitrogen bases of the coding strand in a transcription unit
is 5' – ATGAATG – 3', the sequence of bases in its RNA transcript would be 1
(A) 5' – AUGAAUG – 3'
(B) 5' – UACUUAC – 3'
(C) 5' – CAUUCAU – 3'
(D) 5' – GUAAGUA – 3'
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11. Match the following genes of the lac operon listed in column ‘A’ with their
respective products listed in column ‘B’ : 1
A B
Gene Products
a. ‘i’ gene (i) -galactosidase
b. ‘z’ gene (ii) lac permease
c. ‘a’ gene (iii) repressor
d. ‘y’ gene (iv) transacetylase
Select the correct option :
Options :
a b c d
(A) (i) (iii) (ii) (iv)
(B) (iii) (i) (ii) (iv)
(C) (iii) (i) (iv) (ii)
(D) (iii) (iv) (i) (ii)
12. The human chromosome with the highest and least number of genes in them
are respectively : 1
(A) Chromosome 21 and Y. (B) Chromosome 1 and X.
(C) Chromosome 1 and Y. (D) Chromosome X and Y.
Question number 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, 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.
13. Assertion (A) : In birds the sex of the offspring is determined by males. 1
Reason (R) : Males are homogametic while females are heterogametic.
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14. Assertion (A) : “Biodiversity hotspots” are the regions which possess
high levels of species richness, high degree of endemism. 1
Reason (R) : Total number of biodiversity hotspots in the world is 22
with two of these hotspots found in India.
15. Assertion (A) : AIDS is a syndrome caused by HIV. 1
Reason (R) : HIV is a virus that damages the immune system with
DNA as its genetic material.
16. Assertion (A) : In molecular diagnosis, single stranded DNA or RNA
tagged with radioactive molecule is called a probe. 1
Reason (R) : A probe always searches and hybridises with its
complementary DNA in a clone of cells.
SECTION – B
17. If the base adenine constitutes 31% of an isolated DNA fragment, then
write what will be the expected percentage of the base cytosine in it.
Explain how did you arrive at the answer given. 2
18. Observe the population growth curve and answer the questions given
below :
(a) State the conditions under which growth curve ‘A’ and growth curve
‘B’ plotted in the graph are possible. 1
(b) Mention what does ‘K’ in the graph represent. 1
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19. 5' – G A A T T C – 3'
3' – C T T A A G – 5'
(a) Name the restriction enzyme that recognises the given specific
sequence of bases. What are such sequence of bases referred to as ? 1
(b) What are the arrows in the given figure indicating ? Write the result
obtained thereafter. 1
20. List the events that reduce the Biochemical Oxygen Demand (BOD) of a
primary effluent during sewage treatment. 2
21. (a) “Farmers prefer apomictic seeds to hybrid seeds.” Justify giving two
reasons. 2
OR
(b) Mention one advantage and one disadvantage of amniocentesis. 2
SECTION – C
22. Explain the processing of heterogeneous nuclear RNA (hnRNA) into a
fully functional mRNA in eukaryotes. Where does this processing occur in
the cell ? 3
23. (a) “Mother’s milk is considered very essential for the new born infant.”
Justify. 1
(b) What is a ‘vaccine’ ? Explain the principle on which it works. 2
24. (a) Tropical regions harbour more species than the temperate regions.
How have biologists tried to explain this in their own ways ? Explain. 3
OR
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(b) (i) What does an ecological pyramid represent ?
(ii) The Ecological pyramids may have an ‘upright’ or an ‘inverted’
shape. Justify with the help of suitable examples. 3
25. State why plant breeders are interested in artificial hybridisation
programme. How do they carry out this process ? 3
26. (a) What are transgenic animals ?
(b) Name the transgenic animal having the largest number amongst all
the existing transgenic animals.
(c) State any 3 reasons for which these types of animals are being
produced. 3
27. (a) Construct a pyramid of biomass in sea with phytoplankton and
fishes. Explain giving reasons about the characteristic of the
constructed pyramid.
(b) In which condition will the pyramid remain always upright ? 3
28. (a) Why does DNA replication occur within a replication fork and not in
its entire length simultaneously ?
(b) “DNA replication is continuous and discontinuous on the two strands
within the replication fork.” Explain with the help of a schematic
representation. 3
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SECTION – D
Q. No. 29 and 30 are case based questions. Each question has 3 sub-
questions with internal choice in one sub-question.
29. In a human female, the reproductive phase starts on the onset of puberty
and ceases around middle age of the female. Study the graph given below
regarding menstrual cycle and answer the questions that follow :
(a) Name the hormones and their source organ, which are responsible
for menstrual cycle at puberty. 1
(b) For successful pregnancy, at what phase of the menstrual cycle an
early embryo (upto 3 blastomeres) should be Implanted in the Uterus
(IUT) of a human female who has opted for Assisted Reproductive
Technology (ART) ? Support your answer with a reason. 1
(c) Name the hormone and its source organ responsible for the events
occurring during proliferative phase of menstrual cycle. Explain the
event. 2
OR
(c) In a normal human female, why does menstruation only occurs if the
released ovum is not fertilised ? Explain. 2
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30. Read the following passage and answer the questions that follow :
“Mosquitoes are drastically affecting the human health in almost all the
developing tropical countries. Different species of mosquitoes cause very
fatal diseases so much so that many humans loose their life and if they
survive, are unable to put in productive hours to sustain their life. With
the result the health index of the country goes down.”
(a) Name the form in which Plasmodium gains entry into (i) human
body (ii) the female Anopheles body. 1
(b) Why do the symptoms of malaria not appear in a person immediately
after being bitten by an infected female Anopheles ? Give one reason.
Explain when and how do the symptoms of the disease would appear. 2
OR
(b) Explain the events which occur within a female Anopheles mosquito
after it has sucked blood from a malaria patient. 2
(c) Name a species of mosquito other than female Anopheles and the
disease, for which it carries the pathogen. 1
SECTION – E
31. (a) (i) Draw a diagram of a human sperm. Label any four parts and
write their functions. 4
(ii) In a human female, probability of an ovum to get fertilized by
more than one sperm is impossible. Give reason. 1
OR
(b) (i) With the help of labelled diagram only, show the different
stages of embryo development in a dicot plant. 4
(ii) Endosperm development precedes embryo development. Justify. 1
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32. (a) (i) Draw a schematic diagram of the cloning vector pBR 322 and
label (1) Bam HI site (2) gene for ampicillin resistance (3) ‘ori’
(4) ‘rop’ gene.
(ii) State the role of ‘rop’ gene.
(iii) A cloning vector does not have a selectable marker. How will it
affect the process of cloning ?
(iv) Why is insertional inactivation preferred over the use of
selectable markers in cloning vectors ? 5
OR
(b) (i) Name the nematode (scientific name) that infects the roots of
tobacco plant and reduces its yield.
(ii) Name the vector that is used to introduce nematode-specific
genes into the host plant (tobacco).
(iii) How do sense and anti-sense RNAs function ?
(iv) Why could parasite not survive in a transgenic tobacco plant ? 5
33. (a) Work out a dihybrid cross upto F2 generation between pea plants
bearing violet coloured axial flowers and white coloured terminal
flowers using Punnet’s square. Give their F2 phenotypic ratio. State
the Mendel’s law of inheritance that was derived from such a cross. 5
OR
(b) Explain the process of transcription in prokaryotes. How is it
different from transcription in eukaryotes ? 5
____________
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