ISC (Science) ISC Class 12 - CISCE Important Questions for Biology (Theory)

Name the antibody which is most effective in allergies.

Give one significant difference between primary lymphoid organs and secondary lymphoid organs. Give one example of each.

A substance that stimulates the production of antibodies is called ______.

Briefly explain the role of the following in providing defence against infection in the human body:

B-cells

Briefly explain the role of the following in providing defence against infection in the human body:

T-cells

What are the vestigial organs?

Give any one example of a vestigial organ in human body.

If a person shows the production of interferons in his body, then he is suffering from ______.

Assertion: Lymphocytes originate and proliferate in primary lymphoid organs.

Reason: Spleen is a secondary lymphoid organ.

Observe the relation between the first two words and then fill in the fourth word.

Histamine: Mast cells :: Antibody: ______.

Expand DDT

Give reasons for the following:

Nitrogenous fertilizers are not applied in fields where leguminous crops grow.

Why are the spores of Bacillus thuringiensis used as bioinsecticide?

Give the biological name of the following:

The mould from which penicillin is obtained.

Give the biological name of the following:

The microbe used to control insect larvae growing on cotton.

Give the biological name of the following: 

The microbe used to produce Swiss cheese.

Give the biological name of the following:

The fungus that is being developed as a bio-control agent.

Give the biological name of the following:

A symbiotic nitrogen-fixing bacterium found in root nodules.

Which one of the following factors is responsible for activation of protoxin into active Bt toxin of Bacillus thuringiensis?

Home-made fruit juices are turbid, while the bottled ,fruit juices purchased from the market are clear. Give a reason for this difference.