AP BIOLOGY

Detailed explanation-1: -Damage to DNA and other external factors are evaluated at the G1 checkpoint; if conditions are inadequate, the cell will not be allowed to continue to the S phase of interphase. The G2 checkpoint ensures all of the chromosomes have been replicated and that the replicated DNA is not damaged before cell enters mitosis.

Detailed explanation-2: -These data indicate that the G1 checkpoint is activated in response to mitotic DNA damage in the presence of p53, and that the mitotic DNA damage response is connected to the G1 checkpoint by p53. If cells continue to possess damaged DNA, apoptosis is induced in a p53-dependent manner.

Detailed explanation-3: -The G1 checkpoint determines whether all conditions are favorable for cell division to proceed. The G1 checkpoint, also called the restriction point (in yeast), is a point at which the cell irreversibly commits to the cell division process.