Gujarat Board Class 12 Biology Sample Papers 2007

Sample Paper – 2007

Class – XII

Subject – Biology


General Instructions:

i. All questions are compulsory.

ii. 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.

iii. 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.

iv. Wherever necessary, the diagrams drawn should be neat and properly labeled.

[Section – A]

1. What is the Ploidy of PEN ?

2. Which enzyme is known as ‘molecular scissors’?

3. Name the Ecological pyramid that can be inverted in Tree ecosystem.

4. Expand MOET. Write its one advantage.

5. Which are the nuclei that fuse to form endosperm?

6. Define Biofortification.

7. What is a mutagen? Give two examples.

8. Give the reason why bottled fruit juices bought from the market is clearer as compared to those made at home.

[Section – B]

9. Give two advantages of Saheli. What is sterilisation?

10. What is Selectable Markers? Give one example.

11. Why is the length of a food chain in an ecosystem generally limited to 3-4 trophic levels? Explain with an example.

12. Give different ways for the prevention and control of use af drugs and alcohols among the youth.

13. How is polyspermy prevented in humans?

14. List any four factors which may lead to the loss of biodiversity.

15. Why the length of a food chain in an ecosystem is generally limited to four trophic levels. Explain with example.

16. Study the following carefully and explain why Mutation did not cause any adverse change in the structure of protein H in spite of change in the molecular structure of the gene which codes the protein H. (here C = codons, a = amino acids)

                     Codons for Perotein H: C1-C2-C3-C4-CGU-GGC-C7

                     Amino acids in Perotein H: a1-a2- a3- a4- arg- Gly – a7

                     Mutation : C1-C2-C3-C4-CGU-GGA-C7

                     Structure of Perotein H : No change

17. What are sacred groves? What is their role in Biodiversity conservation?

18. What measures would you take to prevent water borne disease?

[Section - C]

19. Why does one get two peaks in the graphical representation of effects of disruptive selection? Differentiate it from stabilizing selection.

20. How does the gene of an enzyme a-galactosidase can be used as selectable marker? How is it better then other traditional markers like antibiotic resistance genes?

21. Why is the length of a food chain in an ecosystem generally limited to 3 - 4 trophic levels? Why do you think that DFC is the major source of energy for Terrestrial ecosystem?

22. Menstrual cycle completes in three phases. Name them. Also write changes occur in the following organs in different phases:

                  a. Ovaries

                  b. Fallopian tubes

                  c. Uterus

23. Evolution is a continuous process. Give evidences for evolution from

                    a. Paleontology

                     b. Morphology and anatomy

                    c. Biochemical

24. Differentiate inbreeding and out breeding. What type of danger is associated with inbreeding? Name two animal breeds which are developed by cross breeding.

25. Give a schematic representation showing the life cycle of Plasmodium. What is the effect of Haemozion in our body?

                               OR

How does bio-fertilizer enrich the fertility of soil?

26. Differentiate between:

i. Sexual and Asexual Reproduction.

ii. Epicotyl and Hypocotyl.

iii. Apomixis and Polyembryony.

27. What are the advantages of Genetically Modified Organisms (GMO)?

[Section - D]

28. Explain Origin and Evolution of Man.

                                     OR

Give the Diagrammatic Sectional view of Ovary. Explain Oogenisis.

29. What is gene therapy? Illustrate using the example of ADA disease

                                      OR

How does restriction enzyme function? Show it along with diagrammatic representation.

30. Who demonstrated the semi-conservative replication of DNA? Explain the procedure in detail.

                                      OR

Describe the different causes of Biodiversity Loss.