Evolution — BIOLOGY STD 12 Science — Question

Multiple allelism can be investigated only in populations. Justify.

Two statements are given-one labelled Assertion and the other labelled Reason. Select the correct answer to these questions from the codes (a), (b), (c) and (d) as given below.

1. Both assertion and reason are true and reason is the correct explanation of assertion.
2. Both assertion and reason are true but reason is not the correct explanation of assertion.
3. Assertion is true but reason is false.
4. Both assertion and reason are false.

Assertion: Organs of pig such as heart, pancreas, etc., for human use can be grown through transgenic animals.
Reason: Transgenic pigs show improved growth and meat production.

Name the process of the rupture of Graafian follicle and the subsequent release of the egg from the ovary.

Why are pollens preserved for a long time.

Name the respective pattern of inheritance where F, phenotype:

1. Does not resemble either of the two parents and is in between the two.
2. Resembles only one of the two parents.

Transgenic plants are:

1. Produced by a somatic embryo in an artificial medium.
2. Generated by introducing foreign DNA into a cell and regenerating a plant form.
3. Produced after protoplast fusion in an artificial medium.
4. Grown in an artificial medium after hybridization in the field.

Write analogy.

In which position is the phosphate group linked to a nucleoside? Name the linkage too.

Retroviruses have no DNA. However, the DNA of the infected host cell does possess viral DNA. How is it possible?

How is fertilisation by a self-incompatible pollen prevented?