AP 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: -DNA replication. If the checkpoint mechanisms detect problems with the DNA, the cell cycle is halted, and the cell attempts to either complete DNA replication or repair the damaged DNA.

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. Positive regulator molecules allow the cell cycle to advance to the next stage.

Detailed explanation-4: -Cell-cycle checkpoints prevent the transmission of genetic errors to daughter cells. There exist three major cell-cycle checkpoints; the G1/S checkpoint, the G2/M checkpoint, and the spindle assembly checkpoint (SAC).