Question

How do genes control the cell cycle?

Answer 1

Hint: Cell Cycle is the complex process of cell division in eukaryotes. It is the cell’s way of replicating itself in an organized manner. To ensure that the DNA of the replicating cell is copied properly, the process is strictly regulated. Subsequently, any blunders in the process are repaired and each daughter cell receives a complete set of chromosomes.

Complete answer:
The ensuing daughter cells receive the suitable quantity of genetic information originally present within the parent cell, the cell division process is strictly regulated by several enzymes, proteins, and cytokines in every phase.

Cell Cycle Checkpoints:
A checkpoint in the cell cycle is a stage at which the cell inspects internal and external cues and decides whether or not to advance with division.
The 3 important checkpoints are-
-The G1 checkpoint.
-The G2 checkpoint.
-The spindle checkpoint, at the conversion from metaphase to anaphase.

At G1 checkpoint, the cell might assess the subsequent factors:
-Cell Size.
-Nutrients adequacy.
- Molecular signals such as growth factors.
-DNA damage.

At G2 checkpoint, the cell might assess the following factors:
-DNA damage.
-DNA replication completeness.

If any damage to the cell is perceived at this stage, the cell will stop the division process to allow for reparation. If the impairment to the ell is beyond repair, the cell may undertake apoptosis. This self-destruction or “suicide” of the cell ensures that damaged DNA is not passed on to daughter cells.

At spindle checkpoint, the cell might assess the following factors:
-Chromatids’ attachment to the spindle microtubules.
-The cycle will not go ahead with division until all the chromosomes are firmly attached to no less than 2 spindle fibers from fronting poles of the cell.

Note: To conclude, the 'checkpoint genes' screen whether a cell's DNA has been duplicated completely, regardless of whether it is damaged.
These checkpoint controls whether to postpone or stop the cell cycle while simultaneously engaging in repairing. After the preparation, the cell cycle continues.