AP BIOLOGY

Detailed explanation-1: -At the heart of the cell-cycle control system is a family of protein kinases known as cyclin-dependent kinases (Cdks). The activity of these kinases rises and falls as the cell progresses through the cycle.

Detailed explanation-2: -Cell cycle checkpoints are surveillance mechanisms that monitor the order, integrity, and fidelity of the major events of the cell cycle. These include growth to the appropriate cell size, the replication and integrity of the chromosomes, and their accurate segregation at mitosis.

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: -M checkpoint – nuclear division setup check It is also called the spindle checkpoint because the cell examines whether all sister chromatids are correctly attached to the spindle microtubules that separate them. If not, the cell pauses mitosis until all sister chromatids have been attached in the right way.