NEET BIOLOGY

Detailed explanation-1: -The G2 checkpoint bars entry into the mitotic phase if certain conditions are not met. As at the G1 checkpoint, cell size and protein reserves are assessed. However, the most important role of the G2 checkpoint is to ensure that all of the chromosomes have been replicated and that the replicated DNA is not damaged.

Detailed explanation-2: -G2/M checkpoints include the checks for damaged DNA, unreplicated DNA, and checks that ensure that the genome is replicated once and only once per cell cycle. If cells pass these checkpoints, they follow normal transition to the M phase.

Detailed explanation-3: -The G2-M DNA damage checkpoint is an important cell cycle checkpoint in eukaryotic organisms that ensures that cells don’t initiate mitosis until damaged or incompletely replicated DNA is sufficiently repaired.

Detailed explanation-4: -This unleashes cyclin E-CDK2 and cyclin A-CDK2 activity, allowing further RB phosphorylation, exit from G1 and entry into S phase. The G1/S checkpoint is activated upon detection of DNA damage.