Human Reproduction — BIOLOGY STD 12 Science — Question

Maize Seed.

A set of terms are given below (box) followed by few statements in a box.

Outbreeding, Inbreeding, Out-crossing, Cross-breeding, Interspecific hybridisation.

Pick the correct term and write it against the appropriate statement.

1. Male and female animals of two different related species are mated.
2. Superior males of one breed are mated with superior females of another breed.
3. Mating of animals within the same breed, but having no common ancestors on the either side of their pedigree up to 4-6 generations.
4. Mating of more closely related individuals within the same breed for 4-6 generations.

How do surgical procedures prevent conception in humans? Explain the way it is achieved in human males.

A cross between a normal couple resulted in a son who was haemophilic and a normal daughter. In course of time, when the daughter was married to a normal man, to their surprise, the grandson was also haemophilic.
Represent this cross in the form of a pedigree chart. Give the genotypes of the daughter and her husband.

Meiotic division during oogenesis is different from that in spermatogenesis. Explain how and why?

Mention two evolutionary features of mammals.

What are the functions of DNA polymerase?

“Genes contain the information that is required to express a particular trait.” Explain.

From what you have learnt, can you tell whether enzymes are bigger or DNA is bigger in molecular size? How did you know?

What is aquaculture? Give example of an animal that can be multiplied by aquaculture.