Cell cycle checkpoints are critical control mechanisms in the cell cycle that ensure proper cell division. They monitor the cell's progress through different phases, such as G1, S, G2, and M, to verify that conditions are favorable for division and that the DNA is intact. If any issues are detected, the checkpoints can halt the cycle, allowing for repairs or triggering cell death if necessary. There are three main checkpoints: the G1 checkpoint, which assesses cell size and DNA integrity; the G2 checkpoint, which checks for DNA damage before mitosis; and the M checkpoint, which ensures that chromosomes are properly aligned before separation. These checkpoints help maintain genomic stability and prevent the development of diseases like cancer.