Question

Mitotic cyclins control the progression of S phase and mitosis. G1 phase and G2 phase. S phase and G2 phase. G2 phase and mitosis​

Answer 1

Answer:

The cell cycle involves different stages such as interphase, the Mitotic phase followed by cytokinesis.

The interphase involves G0 phase, G1 phase, Synthesis or S phase and G2 phase. The G stands for Gap phase.

The interpase involves the preparation of cellular contents, duplication of DNA. Then during mitosis karyokinesis occurs which is the division of duplicated chromosomes. And then through cytokinesis, the cytoplasmic contents also divides yielding two daughter cells.

Most of the cells normally enter into resting phase I.e., G0 phase and then start the process of cell division again. But some cells enter into G0 phase after the division and remain for longer duration. And this stage is called as quiescent or inactive stage. The mature heart muscle cell and nerve cell are the typical examples for this.

There are also some checkpoints in the cell cycle to check for any damage in the DNA from one phase to another phase and is mediated by Cyclins.

Apart from cyclins, the cyclin-dependent kinase also control the cell division.

These kinases are the enzymatic proteins which were activated by the binding of cyclins to it.

As the levels of different cyclins were different at each phase the amount of kinase activity is also regulated.

The kinases phosphorylates the target proteins which inturn helps in cell cycle such as break down of nuclear membrane during mitotic phase and promoting DNA replication in interphase.

These kinases were also down regulated by phosphorylating the sites where cyclin binds.

Therefore, cyclin dependent kinases can control cell cycle activities.

So, the correct answer is 'Cell cycle activities'

Answer 2

Answer:

The orderly series of events that lead to duplication of cell content followed by division of a cell into daughter cells is termed as the cell cycle. It consists of two phases, namely interphase and M phase. The M phase of cell cycle is marked by the division of nucleus and cytokinesis to produce daughter cells. Interphase is the period between two subsequent M phases and consists of three phases: