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PSEB Class XII Biology Sample Question Paper 2019-20 : Punjab School Education Board

Board : Punjab School Education Board PSEB
Class : Class XII
Subject : Biology
Document Type : Sample Question Paper/ Model Test Paper
Year : 2019-20
Website :

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PSEB XII Biology Sample Question Paper

Download the Sample question paper of Class XII Biology from the official website of Punjab School Education Board.

Related  : PSEB 12th Class Chemistry Sample Question Paper 2019-20 :


1. There are a total of 27 questions and five sections in the question paper. All questions are compulsory.
2. Section A contains question numbers 1 to 5, multiple choice questions of one mark each.

3. Section B contains question numbers 6 to 12, short answer type I questions of two marks each.
4. Section C contains question numbers 13 to 21, short answer type II questions of three marks each.

5. Section D contains question number 22 to 24, diagrammatic/illustrative short answer type questions of three marks each.
6. Section E contains question numbers 25 to 27, long answer type questions of five marks each.

7. There is no overall choice in the question paper. However, internal choices are provided in two questions of one mark, one question of two marks, two questions of three marks and all three questions of five marks. An examinee is to attempt any one of the questions out of the two given in the question paper with the same question number.

Section A

1. Vegetative progation in onion occurs by
a) Offset
b) Bulb
c) Sucker
d) Rhizome
The process through which female gamete undergo development into new organism without fertilization is called
a) Parthenocarpy
b) Parthenogenesis
c) Apomixis
d) Self incompatibility

2. What are the motives that stimulate the youngsters to take drugs
a) Peer pressure
b) Desire for excitement
c) To escape from frustration
d) All of the above
The term totipotency refers to the capacity of a
a) Cell to generate whole plant
b) Bud to generate whole plant
c) Seed to germinate
d) Cell to enlarge in size

3. The first isolated type II restriction endonuclease enzyme is.
a) Eco RI
b) Hind –II
c) Bam-II
d) Eco R1I

4. The part of Human insulin which is removed during maturation of pro insulin to insulin is
a) C – peptide
b) A –peptide
c) D -peptide
d) B -peptide

5. An example of Ex-situ conservation is
a) Seed bank
b) National park
c) Sacred Grove
d) Wildlife santuary

Section B

6. How do Leydig cells help in spermatogenesis
Write down the function of
a. Corpus luteum
b. Endometrium

7. Write any two points of difference in test cross and back cross
8. If a double standard DNA has 20 % of cytosine, what will be the percentage of adenine in this DNA.
9. Write down two points of difference between innate and acquired immunity.

10. Do you think microbes can also be used as source of energy? If yes how?
11. What are Cry proteins? Name the organism that produces it.
12. How does algal bloom destroy the quality of fresh water body?

Section C

13. Briefly discuss any two assisted reproductive techniques that can help infertile couples to have child.
14. A child has blood group O. If the father has blood group A and mother has blood group B work out the genotype of parents and the possible genotypes of other offsprings.
15. How did Hershey and Chase differentiate between DNA and protein in their experiment while proving that DNA is the genetic material ?

16. The following diagram represents a variety of beaks of finches that Darwin found in Galapagos Islands Briefly discuss the phenomena that Darwin explained on the basis of his above mentioned study.
What are connecting links? Give two examples.

17. Briefly describe various steps involved in plant breeding.
18. Microbes can be used to decrease the use of chemical fertilizers and pesticides. Explain how this can be accomplished?
19. Expand PCR.How it helps in amplification of gene of interest?
20. What are transgenic animals? How are transgenic animals helpful to mankind?

21. Give an account of energy flow in an ecosystem
Briefly discuss
a. Catalytic converter
b. Biological magnification

Download XII Biology Sample Question Paper :

Section D

22. Draw a neat, well labeled diagram showing the various parts of typical angiosperm ovule.
23. The following diagram represents the structure of an antibody molecule. Observe the structure carefully and label the parts A, B and C of this diagram.

24. The following diagram depicts the pyramid of number in aquatic ecosystem. Observe the diagram carefully and answer the following questions

A. Label the part A in this diagram
B. Label the part B in this diagram
C. The pyramid of number in aquatic ecosystem is
a. Always straight
b. Always Inverted
c. May be straight or inverted
d. None of the above

Section E

25. Explain the development of male gametophyte in angiosperms. Illustrate the answer with suitable diagrams.
What is spermatogenesis? In which part of testes does it take place? Briefly describe the process of spermatogenesis with help of suitable diagram.

26. In a medium where E.Coli was growing, lactose was added, which induced Lac operon. Then, why does Lac operon shut down sometime after addition of lactose in the medium. Illustrate your answer with suitable diagram.
A. ‘Ontogeny repeats phylogeny’ Justify.
B. Describe Darwin’s theory of natural selection.

27. Explain why ecological succession will be faster in a forest devastated by fire than on a bare rock? Also compare succession in case of an abandoned land after floods with that of bare rock.
What kind of threats to the biodiversity may lead to its loss?

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