Hihi!
The two checkpoints during the cell cycle that regulate cell division are right before S phase and M phase! Cell cycle checkpoints are control mechanisms necessary for proper cell division. In the cell cycle, there are two checkpoints: the G1 checkpoint and the G2 checkpoint. The G1 checkpoint is right before the S phase, and G2 checkpoint is right before the M phase. If something is wrong at the G1 checkpoint, the cell will not enter the cell cycle! It is important to be delayed before cell enters S phase where DNA replication commences.The G2 checkpoint is a DNA damage checkpoint and if DNA is damaged, entering the cell cycle is delayed before mitosis (M phase). If you need anything else please ask!
I hope I helped!
-Jailbaitasmr