What happens at the G1 checkpoint of interphase?

At the G1 checkpoint of interphase, the cell assesses whether it is ready to proceed to DNA synthesis (S phase). It evaluates factors such as cell size, nutrient availability, and DNA integrity. If conditions are favorable, the cell moves forward; if not, it may enter a resting state (G0 phase) or initiate repair processes. This checkpoint is crucial for preventing damaged DNA from being replicated.