Question

What happens during Anaphase, and what molecule must be degraded to allow
Anaphase to progress? Explain the difference between events of Anaphase A and Anaphase B.

Why must we have cellular division as well as programmed cell death (apoptosis)?

Answer 1

An anaphase promoting complex (APC) is formed during anaphase. This complex destroys four proteins for anaphase to progress

1. A protein, securin which binds the two chromosomes together.
2. Cohesin is destroyed.
3. S cyclins
4. M cyclins.

Destruction of these four proteins results in separation of daughter strands.

Anaphase is divided into two stages: - Anaphase A or early anaphase and Anaphase B or late anaphase. Both these phases are involved in separation of daughter chromosomes. In Anaphase A microtubules associated with kinetochore are degraded and shortened in length.

In Anaphase B, the poles are separed and move farther apart, so that the separated chromosomes can reach the poles.

Cellular division and PCD: - Both these phenomenon are required to maintain continuity of life. Everyday, cells undergo wear and tear and are dead. Cellular division restores these dead cells.

PCD is the phenomenon to kill old and worn off cells, for e.g. RBCs undergo PCD after 120 days. New RBCs are restored in the body via cellular division.