AP BIOLOGY

Detailed explanation-1: -Question: Which of the following is NOT a checkpoint in the cell cycle? All the options bellow are all checkpoints in the cell cycle. The G1/S checkpoint checks that the integrity of the DNA before synthesizing a copy of it.

Detailed explanation-2: -The primary G1/S cell cycle checkpoint controls the commitment of eukaryotic cells to transition through the G1 phase to enter into the DNA synthesis S phase.

Detailed explanation-3: -The main cell cycle checkpoints are the G1/S checkpoint, the intra-S checkpoint, and the G2/M checkpoint [60]. The transition through stages of the cell cycle is regulated by the action of cyclin-dependent kinases, which are key targets for modulations induced by different cellular stimuli, including DNA damage.

Detailed explanation-4: -There are many checkpoints in the cell cycle, but the three major ones are: the G1 checkpoint, also known as the Start or restriction checkpoint or Major Checkpoint; the G2/M checkpoint; and the metaphase-to-anaphase transition, also known as the spindle checkpoint.