Biology (CBSE Guess Paper Class XII)[Set-2]

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Download CBSE Biology Guess Paper Class XII (12th) 2009

CBSE SAMPLE PAPER 2009

Biology Class XII

Time: 3hours                                                            Max.Marks:70

GENERAL INSTRUCTIONS:

i.                   All questions are compulsory.

ii.                 The question paper consists of tour sections A, B, C end D. Section-A consists 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.             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 questions of five marks weight age. A student has to attempt only one of the alternatives in such questions.

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

 

SECTION – A

 

1.     At what stage of life is cogenesis initiated in a human female? When does the acolyte complete cogenesis?

2.     AaBb was crossed with aabb. What would be the phenotypic ratio of the progeny? Mention the term to denote this kind of cross.

3. In F.Gritiith's experiment, how did the no virulent stage of Streptococcus pneumonia become virulent?

4. State the use of:

i. trichoderma with respect to organ transplant, and

ii. nucleopolyhedrovirus with respect to pest management

 

5.     Bacteria that convert milk into curd play two other beneficial roles. What are they?

6. After successful In-vitro fertilization, the fertilized egg begins to divide. Where is the egg transferred before it reaches the 8-cell stage and what is the technique named?

7.     Why thermoregulation is more effectively achieved in larger animals than in smaller one?

8.   City an example of an inverted ecological pyramid. What kind of pyramid of energy would it have? 

SECTION-B

 

9.     Which one out of the evrythermal or stenothermal species is likely to survive increased global temperature? Give one reason for your answer.

10.  Given below is an incomplete flow chart showing influence of hormones on gametogenesis in males. Observe the flow chart carefully and fill in the blanks A. B, C and D.


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