What are the 3 cell cycle "checkpoints?"

G1 checkpoint G2 checkpoint Spindle checkpoint

G1 check point is the main check point that controls if cell continue to divide or stop dividing this depends on many factors : 1. type of cell eg neuron will stop dividing and enter G0 while skin cell will continue to divide 2.if cell have enough nutrients , Growth factors , appropriate size , free from DNA defects

G2 check point occurs between G2 and : it makes sure that replication of DNA occurred completely and there are no , if there are mutations they must corrected first before going into mitosis , if they cannot be corrected the cell must die to prevent future cells from carrying this defect

Spindle check point occur between metaphase and anaphase to make sure chromosomes are attached to the spindles.