Question Bank [2022] — BIOLOGY STD 12 Science — Question

Restriction enzymes present in the cloning site of a vector should not have more than one recognition site. Comment.

Why do moss plants produce very large number of male gametes? Provide one reason. What are these gametes called?

Write down the possible levels of regulation of gene expression in eukaryotes.

Give Reasons : When Mendel crossed a tall pea plant with a dwarf pea plant the offspring obtained from this cross were all tall.

Give Reasons: Viruses obtained by infecting bacteria having radioactive phosphorus contained radioactive DNA (labelled DNA), but not radioactive proteins.

Fertilization in angiosperms is double fertilization.

In a cross between two tall pea plants, some of the offsprings produced were dwarf. Show with the help of Punnet square, how this is possible.

The flower of brinjal is referred to as chasmogamous while that of beans is cleistogamous. How are they different from each other?

Enlist the steps in the process of chemical evolution.

What happens to an individual when a regular dose of drugs/alcohol is abruptly discontinued? What characteristics manifest in the individual under such a situation?