केंद्रीय विद्यालय संगठन, अहमदाबाद संभाग

KENDRIYA VIDYALAYA SANGATHAN, AHMEDABAD REGION

प्री-बोर्ड परीक्षा 2022 / अर्डिावषडक परीक्षा

PRE-BOARD EXAMINATION 2022/ HALF YEARLY EXAM
(SET -1A)
SUBJECT: BIOLOGY M.M.: 80
CLASS: XII TIME: 3 Hours

GENERAL INSTRUCTIONS:
1. All the questions are compulsory.
2. This Question Paper contains Five sections and 33 questions.
3. 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.
4. There are no overall choice. However, internal choices have been given in some questions.
A student has to attempt one out of the two choices in such questions.
5.Wherever necessary, neat and proper diagrams should be drawn.

(Section -A) (1X16=16)

1. A gene in pig named I32cD control the expression of body hairs as well
as pinna length of ear. This gene seems to exhibit the phenomenon of:
(A) Multiple alleles (B) Polygenic Trait
(C) Incomplete Dominance (D) Pleiotropy

2. Proteins called interferons are a kind of innate immunity of the type:

(A) Physical barrier (B) Cellular barrier

(C) Cytokine barrier (D) Physiological barrier

3. Trisomy of 21st chromosome is characterised by:

I – Furrowed Tongue
II – Characteristic Palm crease
III – Rudimentary Ovaries
IV – Gynaecomastia
V – Lack of secondary sexual characters
(A) II and IV only (B) II, III and IV
(C) I, II and V (D) I and II only

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4. In an over populous country which of the following indices always show
gross positive value:
(A) MMR (B) IMR
(C) Sex ratio (D) Birth Rate

5. Brood parasitism is exhibited by:

(A) Tiger (B) Crow

(C) Cockoo (D) Ticks

6. A DNA with 320bp has 250 Thiamine, how many Guanine are present in
the molecule:
(A) 70 (B) 35
(C) 250 (D) None of these.

7. Negative/Neutral (-/0) type of population interaction is exhibited in case

of:
(A) Mutulism (B) Commensalism
(C) Predation (D) Amensalism

8. Which of them is not a water pollinated plant:

(A) Water hyacinth (B) Zostera

(C) Hydrilla (D) Vallisneria

9. Mycorrhiza is a plant-fungus symbiosis where fungus contribution is the

absorption and supply of _______ from soil to plant:
(A) Nitrogen (B) Phosphorus
(C) Carbonates (D) Amides

10. In Gel electrophoresis,

identify the structure “P”
which acts as the base of
the system:

(A) Wells (B) Agarose Gel

(C) UV – Light (D) Ethidium Bromide

11. During sewage treatment, ‘Flocs’ are introduced at the time of:

(A) Anaerobic sludge digestion (B) Secondary Treatment

(C) Preparing Activated Sludge (D) Primary Treatment

12 The ice age between 75,000 – 10, 000 years ago, saw the genesis of:

(A) H. erectus (B) Neanderthal Man

(C) Ramapithecus (D) H. sapiens

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 Question number 13 – 16 consists of two statements – Assertion
(A) and Reasoning (R). Answer these questions selecting the
appropriate options 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 correct but R is False.
D. A is false but R is true.

13. Assertion (A): In molecular diagnosis, single stranded DNA or RNA

tagged with radioactive molecule is called a Probe.
Reason (R): A probe always search and hybridise to its complementary
DNA in a clone of cells.

14. Assertion (A): AIDS is a syndrome caused by HIV.

Reason (R): HIV is a bacterium that damage the immune system.

15. Assertion (A): Fig wasp and Fig tree are a classic case of co-evolution.
Reason (R): It has been observed that species co-evolving as a result of
obligation, also co-extinct if one of the two species becomes
extinct.

16. Assertion (A): The genetic makeup of sperm determines the sex of the
child.
Reason (R): Males are heterogametic while females are homogametic.

(Section -B) (2X5=10)

17. Members of Asteraceae and grasses specialize in producing Apomictic

seeds. Write two methods of production of such seeds.

18. Write two differences between GFC and DFC of an ecosystem.

19. Name the types of age pyramids of human population. Which type of
pyramid is suitably ecologically? Why?

20. Elaborate the term “Transformants” in cloning. Why genes encoding

resistance to antibiotics (eg. Ampicillin) are useful selectable markers for
cloning processes in E.coli?

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21. The chart is showing a
relation of some trait with
reference to Natural
Selection. Which type of
Natural Selection is this.
Write its characteristic
feature?

(Section - C) (3X7=21)

22. Explain the technique developed by Sir Alec Jeffereys using satellite DNA
as probes.

23. Fill in the spaces A, B and C as per the table:

PRODUCT ORGANISM NAME OF

MICROBE

CITRIC ACID FUNGUS A

B BACTERIUM Streptococcus

STATINS C M. purpureus

24. Outbreeding devices have been evolved by certain plant species during
evolution. Explain the reason for this evolution. Mentioning at least two
such devices?
OR
RCH Program has been instrumental in spreading awareness for building
up reproductively healthy society. List three roles of Governmental/ non
– governmental agencies in promoting RCH Program.

25. List three differences between the mode of transcription exhibited in

Prokaryotes and Eukaryotes.

26. Explain the decomposition cycle in a terrestrial ecosystem.

27. Draw steps of gene amplification using a technology that you have
studied in your school.

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28. Discuss the procedure and outcome of the experiment which conclusively
proved that DNA is the genetic material.
OR
“Lac – Operon is a negative regulation”. Prove with the help of its
working.

(Section - D) (2X4=8)

29. Study the Pedigree of a family given

alongside and answer the following
questions:

(A) What conclusion can be drawn

about the inheritance pattern of
this pedigree?

(B) Name the technical term used for

mating between individuals 1 & 2
in generation I.

(C) Write the percentage probabilities

of male & female child inheriting
this type of gene pattern.

(D) Justify your answer given in point

number (C).

30. The data presented here, is showing

contraceptive prevalence among a
sample size of 661 million users.
Answer the following questions:

(A) Who among the sexes (males or

females) take the lead in the
contraception?

(B) Write the technical term used for

female sterilization?

(C) Name a method which is equally

effective in preventing HIV?

(D) “Male sterilization is the least

prevalent method among
contraception”. Justify giving
reason.

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 (Section -E) (3X5=15)

31. (A) Expand GEAC. Write its role.

(B) Discuss the principle and mechanism of pest resistance in plants
using Agrobacterium vectors?
OR
(A) How insertional inactivation acts as selectable marker in cloning
technology? Explain with an example.
(B) Discuss the action of protein crystals formed by BT-gene? Write the
specific target pests of gene cryIAb ?

32. (A) What do you understand by the term c-onc ? What is its significance
in human body?
(B) How metastasis is attained by a healthy cell?

OR
(A) Name one fungus species causing ringworm. Write two characteristic
features of the disease?
(B) Diagrammatically represent the life cycle of Plasmodium.

33. (A) When do the formation of second polar body takes place in female
ovum? What is its significance?
(B) Discuss the journey of zygote till its implantation.

OR

Observe the chart shown below and answer the questions that follows:

(A) Why Follicular phase is also known as “Proliferative Phase”?

(B) List the events of ovary and pituitary around 14th day of the cycle.
(C) Write the role of corpus luteum in menstrual cycle. Which event
trigger menses?

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