Question

The checkpoint in cell cycle plays important role in:
A. Repairing DNA damage.
B. Apoptosis initiation.
C. Assessing DNA damage
D. None of the above

Answer 1

Cell cycle is a complex series of events that involves cell growth and division. It involves a number of phases which prepares the cell to make sure that everything is right to undergo the last phase of the cell cycle, that is mitosis which is very essential for growth and repair.

Complete answer:

The cell cycle is broadly divided into two major phases namely interphase and the mitotic phase.
In the interphase, we can see three more phases. They are ${G_1}$ phase, $S$ phase and the ${G_2}$ phase. This phase is followed by the mitotic phase.
$G$ in the ${G_1}$ and ${G_2}$ refers to a gap in the cell cycle. End of the ${G_1}$ and ${G_2}$ phase there are checkpoints that check for the mistakes in the cell and make sure that the cell can undergo replication or division properly.
So, what exactly the ${G_1}$ phase does is that it makes sure that the cell is ready to undergo replication in the $S$ phase where DNA replication takes place. The cells here increase the proteins, mitochondria, ribosomes and grow larger in size in the ${G_1}$ phase.
Next let's see the $S$ phase. In this phase what happens is that the genetic material is replicated and DNA is doubled.
${G_2}$ phase prepares the cell for mitosis. At the end of ${G_2}$ phase is another checkpoint which checks if the cell is ready to undergo mitosis.
Finally let's see about the mitotic phase. The mitotic phase is the phase of cell division where the cell undergoes division and forms two identical daughter cells.

Hence, the correct answer is option (C).

Note:

After ${G_1}$ phase, the cell has three options – continue the cell cycle by entering $S$ phase, undergo differentiation by entering ${G_0}$ phase or be arrested in ${G_1}$ phase and later enter ${G_0}$ or ${G_1}$ phase.
If the DNA is damaged at ${G_2}$ stage, there will be the repair of DNA or the cell will undergo apoptosis. This is regulated by a gene called ${P^{53}}$. If the ${P^{53}}$ gene is mutated, then the cell will continue to replicate with damaged DNA and it will lead to become a cancerous cell.