Sample Paper – 2008

Class – XII

Subject – Biology



General Instructions:

1. All questions are compulsory.

2. This question paper consists of four Sections A, B, C and D. Section -A contains

8 questions of 1 mark each, Section -B is of 10 questions of 2 marks each,

Section -C has 9 questions of 3 marks each and Section D is of 3 questions of 5 marks each.

3. There is no overall choice .However, an internal choice has been provided

in one question of 2 marks, one question of 3 marks and all the three questions of

5 marks. Attempt only one of the choices in such questions.

4. Wherever necessary, the diagrams drawn should be neat and properly labelled.





1. What is the Ploidy of PEN ? [1]

2. A human zygote has XXY sex chromosomes along with 22 pairs of autosomes

What sex will the individual be? [1]

3. Expand FOAM. What is its significance? [1]

4. Which enzyme is known as ‘molecular scissors’? [1]

5. Name the Ecological pyramid that can be inverted in Tree ecosystem. [1]

6. Explain the term emasculation. When and why does a plant breeder employ [1]

this technique

7. Why is cow dung used in generation of Biogas? [1]

8. Name two animals each that are (i)Oviparous (ii) Viviparous. [1]



9. What are sacred groves ? What is their role in Biodiversity conservation? [2]

10. Mention the advantages of selecting Pea plant for experiment by Mendel. [2]


Why does Mendel’s work gone unnoticed?

11. What measures would you take to prevent water borne disease? [2]

12. What are the disadvantages of human use of Insulin from other animal sources?[2]

13. Name the diseases diagnosed by (a)WIDAL test (b)ELISA test [2]

14. What is Biological Magnification ? [2]

15. Differentiate between Geitonogamy and Allogamy. [2]

16. If the sequence of coding strand in a transcription unit is written as follows :[2]


Write the sequence of mRNA

17. Name the technique used for separation of DNA fragments.What is its principle? [2]

18. Define the term Adolescence. How does Peer pressure effect the personality of child? [2]




19 What is meant by Homologous organs? Give an example [3]

20 Differentiate between Menarche and Menopause. [3]

21 What do the differently written terms ‘Cry’ and ‘cry’ represent? Crystalsof Bt toxin produced by some bacteria do not kill the bacteria themselves, but kill insects such as beetles and mosquitoes etc. Explain why? [3]

22 Bring out differences between Carbon and Phosphorus cycle of ecosystem.[3]

23 What are the three critical research areas of Biotechnology? [3]

24 What is Apiculture ? How is it important for our lives? [3]


How are microbes helpful in Sewage Treatment?

25 Three Codons on mRNA are not recognized by t RNA. What are they ? What is the general term used for them? What is their role in protein synthesis? [3]

26 Why is the length of a food chain in an ecosystem generally limited to 3-4 trophic levels? [3]

27 A colour blind man marries a woman with normal vision ,whose father was colour blind .Work out a cross to show the genotype of couple and their prospective sons. [3]



28. Who demonstrated the semi-conservative replication of DNA? Explain the procedure indetail.


Describe the Fredrick Griffth’s experiment to prove that DNA is the basic genetic material. [5]

29. What are Algal blooms ? How are they formed ? Give two harmful effects of formation of algal blooms in a water body.


What is Global warming ? give its harmful effects . List strategies of reducing global warming. [5]

30. Trace the development of Megaspore mother cell of Flower in mature ovule with the help of labeled diagram.


Write the function of :

(a) Corpus luteum(b) Endometrium(c) Acrosome(d) Sperm tail(e) Fimbriae[5]