Molecular Basis of Inheritance — BIOLOGY STD 12 Science — Question

Define homologous organ. Give one example of an organ homologous to hand of man.

Construct a grazing food chain and a detritus food chain using the following, with five links in each:
Earthworm, bird, snake, vulture, grass, grasshopper, frog, decaying plant matter.

Would you like to choose an exonuclease enzyme while producing a recombinant DNA molecule?

List any four factors which may lead to loss of biodiversity.

Given alongside is an enlarged view of one microsporangium of a mature anther. Mention the characteristics and function of the cells forming wall layer ‘c’.

What is IUCN red list? Give any two uses of this list.

A young boy when brought a pet dog home, started to complain of watery eyes and running nose. The symptoms disappeared when the boy was kept away from the pet.

1. Name the type of antibody and the chemicals responsible for such a response in the boy.
2. Mention the name of any one drug that could be given to the boy for immediate relief from such a response.

A couple with normal vision bear a colourblind child. Work out a cross to show how it is possible and mention the sex of the affected child.

If there are two pathogenic viruses, one with DNA and other with RNA, which would mutate faster? And Why?

Mention the evolutionary significance of the following organisms:

1. Shrews.
2. Lobefins.
3. Homo habilis.
4. Homo erectus.