CBSE Class 12 Biology - Sample Questions and Answers

1. The turkey usually produces females for several generations. How it this possible?
Ans: It is due to parthenogenesis.

2. The meiocyte of an onion plant contains 32 chromosomes. Workout the number of chromosomes found in its endosperm.
     2n=32(Meiocyte will be diploid)
       n=16 (gametes)
     3n=3x16=48( Endosperm is triploid)

3. The gene I that controls the ABO blood grouping in human beings has three alleles IA, IB and i.
a) How many different genotypes are likely to be present in human population?
b) Also, how many phenotypes are possibly present?
ABO bBlood group
a) 6 Genotypes - IAIA, IAi,( A blood group); IBIB, IBi (B blood GROUP), IAIB (AB blood group), ii (O blood group)
b) 4 Phenotypes - A, B, AB, O blood groups

4. Pink out the ancestral line of Cycads from the list given below:-
Ferns, herbaceous lycopods, seed ferns and horse tails.
Ans: seed ferns

5. Name the source of smack. Mention one way in which affects the human body.
Ans: Obtained from Papaver somniferum(Poppy plant)
It acts as depressant

6. In plants, how is alien DNA introduced into the host cell?
Ans: To introduce alien DNA in plants, plant cells are bombarded with high velocity micro particles of gold or tungungsten coated with DNA in a method known as biolistics or gene gun (gene transfer methods).

7. Mr. G eats curd/ yogurt. In this case, which trophic level will be occupy?
Ans: Third trophic level

8. In the absence of the predators, which curve (a) or (b) would appropriately depict the prey populations?
Ans: Curve a
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