NEET BIOLOGY

Detailed explanation-1: -Cell cycle checkpoints are surveillance mechanisms that monitor the order, integrity, and fidelity of the major events of the cell cycle. These include growth to the appropriate cell size, the replication and integrity of the chromosomes, and their accurate segregation at mitosis.

Detailed explanation-2: -The main cell cycle checkpoints are the G1/S checkpoint, the intra-S checkpoint, and the G2/M checkpoint [60]. The transition through stages of the cell cycle is regulated by the action of cyclin-dependent kinases, which are key targets for modulations induced by different cellular stimuli, including DNA damage.

Detailed explanation-3: -Cell-cycle control depends exclusively on post-transcriptional mechanisms that involve the regulation of Cdk activity by phosphorylation and the binding of regulatory proteins such as cyclins, which are themselves regulated by proteolysis.

Detailed explanation-4: -In the cell cycle, there are three major checkpoints-the G1 checkpoint, the G2 checkpoint, and the spindle checkpoint.

Detailed explanation-5: -There exist three major cell-cycle checkpoints; the G1/S checkpoint, the G2/M checkpoint, and the spindle assembly checkpoint (SAC).