PATHOLOGY

Detailed explanation-1: -A checkpoint is a stage in the eukaryotic cell cycle at which the cell examines internal and external cues and “decides” whether or not to move forward with division.

Detailed explanation-2: -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-3: -Each step of the cell cycle is monitored by internal controls called checkpoints. There are three major checkpoints in the cell cycle: one near the end of G1, a second at the G2/M transition, and the third during metaphase.

Detailed explanation-4: -A checkpoint is one of several points in the eukaryotic cell cycle at which the progression of a cell to the next stage in the cycle can be halted until conditions are favorable. These checkpoints occur near the end of G1, at the G2/M transition, and during metaphase (Figure 1).

Detailed explanation-5: -Damage to DNA and other external factors are evaluated at the G1 checkpoint; if conditions are inadequate, the cell will not be allowed to continue to the S phase of interphase. The G2 checkpoint ensures all of the chromosomes have been replicated and that the replicated DNA is not damaged before cell enters mitosis.