The G2 checkpoint is a critical control mechanism in the cell cycle that occurs before a cell enters mitosis. It ensures that the cell has accurately replicated its DNA and is ready to divide. If any DNA damage or replication errors are detected, the checkpoint can halt the cell cycle, allowing for repairs to be made. During the G2 phase, which follows the S phase where DNA is synthesized, proteins such as p53 play a vital role in monitoring the integrity of the DNA. If the damage is irreparable, the cell may undergo apoptosis, or programmed cell death, to prevent the propagation of faulty genetic material.