Question

explain the proves at G2 checkpoint and account for the kinases and cyclins in cell division.

Answer 1

G2 Checkpoint

The G2 checkpoint is an important checkpoint in the cell division . This checkpoint checks whether the DNA is damaged or is incompletely replicated. This checkpoint makes sure that the next step, that is mitosis won't initiate until damaged or incompletely replicated DNA is sufficiently repaired.

Cyclins drive the events of the cell cycle by partnering with a family of enzymes called the cyclin-dependent kinases. A lone cyclin dependent kinase is inactive, but the binding of a cyclin activates it, making it a functional enzyme and allowing it to modify taregt proteins. Cyclins are produced inside the cell. In every stage of cell division cyclin and CDK combination is required to progress to the next phase of the cell cycle. For example: the cyclin which works in G1 phase is G1-S (cyclin D-cdk complex) cyclin which makes it possible to go to next stage that is S phase. In s phase, there is cyclin E-cdk complex. In g2 check point, there is cyclin A-cdk complex. In metaphase chceck point, there is cyclin B-cdk complex. These complexes activate proteins by phosphorelating them and thus makes it possible to go to the next phase of the cell division.