Biodiversity and Conservation — BIOLOGY STD 12 Science — Question

A man with blood group A married a woman with blood group B. They have a son with AB blood group and a daughter with blood group O. Work out the cross and show the possibility of such inheritance.

Why is there a statutory ban on amniocentesis? Why is the technique so named?

Refer to the following diagram of a strand of nucleotide to answer questions a-d.

1. What molecule is represented by S?
2. What molecule is represented by B?
3. How many different types of B are in DNA?
4. What type of bond is represented by the dotted lines?

Where do the following events occur in the life-cycle of Plasmodium?

1. Gametocyte development.
2. Sexual reproduction.
3. Asexual reproduction.

List the features that make a stable biological community.

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?

If a double stranded DNA has 20% of cytosine, calculate the per cent of adenine in the DNA.

Differentiate between Heterochromatin and Euchromatin.

State the measures to prevent AIDS. ### Explain prevention of AIDS.

How is recombinant DNA technology helping in detecting the presence of mutant genes in cancer patients?