Sexual Reproduction in Flowering Plants — BIOLOGY STD 12 Science — Question

Suggest four important steps to produce a disease resistant plant through conventional plant breeding technology.

What are the probable factors that contributed to population explosion in India?

Why is there no need of fertilizer in rice cultivation?

How is predation different from competition?

A3' ............ 5'B
C5’ ........... 3'D.
AB and CD represent two strands of a DNA molecule. When this molecule undergoes replication, forming a replication fork between A and C in the above.

1. Name the templete strand for replication.
2. Using which strand as the templete, will there be continuous synthesis of a complementary DNA strand
3. Complementary to which strand will okazaki segments get synthesised, discontinuous synthesis occurs.
4. What are templete strands and Okazaki pieces?
5. In which direction is a new strand synthesised?

A farmer is advised to sow leguminous seeds inoculated with a bacterial culture that helps in increasing crop yield. Name the bacterium in the culture. How is this bacterium useful to the crop?

What are the aims of plant conservation?

A spermatogonial cell has 30 chromosomes. How many chromosomes will be found in:

1. The primary spermatocyte.
2. The spermatid?

What is meant by monosporic development of female gametophyte?

Does self incompatibility impose any restrictions on autogamy? Give reasons and suggest the method of pollination in such plants.