The cell cycle consists of several key checkpoints: 1. G1 Checkpoint: Assesses cell size, nutrients, and DNA integrity before proceeding to DNA synthesis (S phase). 2. G2 Checkpoint: Ensures that all DNA is correctly replicated and undamaged before entering mitosis (M phase). 3. M Checkpoint (Spindle Checkpoint): Monitors proper chromosome alignment and attachment to the spindle fibers before allowing chromatid separation.
