NEET BIOLOGY

Detailed explanation-1: -Subsequently, apoptosis occurs as a result of G0/G1 phase arrest. Apoptosis as a protective mechanism ensures homeostasis of host cells through cell shrinkage, fragmentation of cellular DNA and formation of ‘apoptotic bodies’ leading to cell death.

Detailed explanation-2: -Cancer cells avoid, in a way, entering the G0 phase because they are genetically modified to divide faster. Therefore, cancer cells might shorten, or skip all together, the G0 phase. What this implies is that cancer cells divide faster than they should since they don’t remain in the G0 phase as long as they should.

Detailed explanation-3: -Hematopoietic cells can undergo apoptosis at all stages of cell cycle as noted by Bertrand. However, mesenchymal or epithelial cells usually undergo apoptosis at the G1/S or G2/M phase of the cell cycle.

Detailed explanation-4: -There are 4 stages of apoptosis: the initiation or stimulus for cell death, the active programmed cell death when the events become irreversible, phagocytosis of the dead cellular material, and inhibitory mechanisms of apoptosis.