Question

Apoptosis:

a. Explain the concept of apoptosis. Why is programmed cell death a necessity for multicellular organisms?

b. Define caspase and apoptosome. How does the apoptosome amplify cell death signals?

Answer 1

Ans a) Apoptosis is a programme cell death or cellular suicide which leads to the elimination of cells without releasing harmful substances into the surrounding area .

Apoptosis is mediated by proteolytic enzyme called caspases which trigger cell death by cleaving specific proteins in the cytoplasm and nucleus.

steps involved-

1 the decision to activate the pathway.

2 the actual suicide of the cell.

3 engulfment of the cell by phagocytes.

4 degradation of engulfed cell.

APOPTOSIS OR PROGRAMMED CELL DEATH is necessary for multicellular organism - apoptosis removes cell during development ,eliminates old cell , unnecessary cells,cancerous and virus infected cells and maintain balance in the body .

example - the formation of fingers and toes of the fetus requires the removal of tissue between them by apoptosis .

Ans b) Caspase-are family or protease enzyme or proteolytic enzyme that mediate apoptosis (programmed cell death).

Apoptosomes- are large quarternary protein structure formed in the process of apoptosis.apoptosomes are found to aid the intrinsic process of apoptosis in the mitochondria. apoptosome is activated by cytochrome c .

caspase 9 interact with apoptosones to initiate apoptosis.apoptosomes also cleavage procaspase 3 and 7 dimer.