NEET BIOLOGY

Detailed explanation-1: -The cell cycle is controlled at three checkpoints. The integrity of the DNA is assessed at the G1 checkpoint. Proper chromosome duplication is assessed at the G2 checkpoint. Attachment of each kinetochore to a spindle fiber is assessed at the M checkpoint.

Detailed explanation-2: -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-3: -Positive Regulation of the Cell Cycle Two groups of proteins, called cyclins and cyclin-dependent kinases (Cdks), are responsible for the progress of the cell through the various checkpoints.

Detailed explanation-4: -The cell cycle is controlled mainly by regulatory proteins. These proteins control the cycle by signaling the cell to either start or delay the next phase of the cycle. They ensure that the cell completes the previous phase before moving on.