What are the main things that aide checkpoints in the regulation and how does each checkpoint varies??
G1 checkpoint checks for cell size, nutrients, growth factors, and if there is DNA damage. If the cell fails this checkpoint, it will either stay in G1 or go to G0. If it passes, the cell will continue to G2.
G2 checkpoint checks for successful replication of DNA. If it fails this checkpoint, the cell will try to fix errors, but if that fails, apoptosis will occur so the cell does not become cancerous. If it passes, the cell will continue to mitosis.
The mitosis/spindle checkpoint will check to see if the chromosomes are attacked to the spindle at the metaphase plate.