Time 3 hrs                                           Class XII                                                         M.M 70

General Instruction :

i)                    All questions are compulsory

ii)                  The question paper consist of four sections A,B,C & 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 whereas section D is of 3 questions of 5 marks each.

iii)                An internal choice has been provided in one question of 2 marks, one question of 3 marks and three question of 5 marks weightage. Attempt only one of the choice in such questions

Section –A

1. When does meiosis occur in organisms which show haplontic type of life cycle?
2. What is the ploidy level of oogonia and spesmatids?
3. Name the type of synthesis ‘a’ and ‘b’ occurring in the replication fork of DNA as shown in this diagram?
4. Name the substance secreted by virus infected cells which protect non infected cells. What type of defence mechanism it is?
5. Name the bioactive molecule produced by Trichoderma polysporum. What function is performed by this melocule?
6. Gene amplification using PCR technique produces a large number of molecules of the foreign gene . name two requirement for the process.                   
7. Name the relationship which exits between two organisms where one is benefited and the other is neither benefited nor harmed.
8. What is meant by PAR?

Section – B

9. Given below are the diagrams depicting transcription of DNA in bacteria.

i)                    Identify 1 and 2.

ii)                  What functions are performed by each of them?

10. What is divergent evolution? Explain taking an example.
11. A man with blood group A married a woman of blood group B. They have ason with AB blood group and a daughter with blood group O. Work out the cross and show the possibility of such inheritance.

OR

The male fruitfly and female fowl are heterogametic while the female fruit fly and the male fowl are homogametic. Why are they called so?

12. Mention the name of the causative agent of malaria. What causes shivering when a person suffers from the disease?
13. A mother of one year old daughter wanted to space her second child. Her doctor suggested CuT .Explain its contraceptive action.
14. Name the interaction in each of the following.

i)                    Cuckoo lays her egg in the crow’s nest.

ii)                  Orchid grows on a mango tree.

iii)                Ticks live on the skin of dogs.

iv)                Sea anemone is often found on the shell of hermit crab.

15. What are the sources of complementary RNA in the RNA mechanism?
16. What is biofortification? Give some examples of vegetables and fruits fortified with nutrients.
17. What are plaindronic nucleotide sequences in the DNA? Explain with suitable example.
18. Represent a cross showing in complete dominance in snapdragon.

Section C

19. i) In which metabolic process ethanol is produced?

ii)                  Name the microbe which is used in the preparation of some of the alcoholic beverages.

iii)                How wine, beer, whiskey, rum and brandy are prepared?

20. Make a labeled diagram of angiospermic ovule.

OR

Explain the function of the following

i) Leydig cells       ii) Synergids                ii) Intrauterine devices

21. A population has been exhibiting genetic equilibrium. Answer the following with regards to the above statement.

i)                    Explain the above statement

ii)                  Name the underlying principle

iii)                List any two factors which would upset the genetic equilibrium of the population.

22. Give definition of test cross. Using punett square, find out the nature of offspring of a test cross. What ratio will be obtained? What is its utility?
23. What are Primers? What role do they play in synthesis of a DNA segment in vitro? What role is played by DNA polymerase.
24. What were the observations made by Alexander von Humboldt? Explain species area relationship?
25. What are cry proteins? Name an organism that produces them? How has man exploited this protein to his benefit.
26. Name the term used for the following:-

i)                    Organism that can feed both on plants and animals.

ii)                  Interconnection of food chains.

iii)                Mass of living material at a particular time at a trophic level .

iv)                Final community which reaches equilibrium during plant succession.

v)                  A species which invades a bare area.

vi)                Another term for nutrient cycle.

OR

Explain the various stages of Primary Succession in a water body.

27. i) Which factors have caused drug or alcohol abuse in adolescents? Mention them.

ii)                  How can infections like AIDS or hepatitis B be caused in adolescents?

iii)                What are the effects of long term use of alcohol on people?

Section –D

28. Name and describe the process which occurs in a female gametophyte of an angiosperm plant when the pollen tube enters it.

OR

Make a labelled diagram showing the difference in the levels of pituitary hormones, development of follicles and development of uterine events during menstrual cycle.

29. Explain the process of replication of DNA molecule.

OR

What is the principle of DNA finger printing? Explain.

30. What is green house effect? How can it caused global warming? Explain.

OR

Define decomposition and describe the process and products of decomposition.