Question

How do cells know when it is time to divide?

Answer 1

The cells are the structural and functional unit of the living body or life. They are the smallest living unit of the body that is capable of sustaining life and perform all the basic life functions. The cells divide with the process of amitosis, mitosis, and meiosis.

Complete answer:
In the whole life of the cell, it undergoes through preparation and division phase over and over in a cyclic manner. This is known as the cell cycle.
The cell cycle consists of three distinct phases that are interphase, karyokinesis, and cytokinesis. The interphase is the most metabolically active phase because the cell here prepares itself for the cell division. Therefore, it is also known as the preparatory phase.
The interphase is further divided into three phases which are the ${G_1}$ - phase, S – phase, and ${G_2} -$phase. The cell takes the decision of division during the ${G_1} -$phase.
During the ${G_1} -$phase the RNA and protein synthesis becomes fast. Most of the cell organelles get duplicated here. The synthesis of ATP and nucleotides increases. Due to this the size of the cell gradually increases. This is where the cell decides whether it has to divide or not. It is known as the transition point. The cells that decide to not divide further enter the ${G_0} -$phase. Antiphase is that phase where the cell is bound to divide and it cannot enter into ${G_1} -$phase or ${G_0} -$phase.

Note:
The ${G_1} -$phase is also known as the first gap phase because the first gap in the cell cycle occurs here. It is also known as the post-mitotic or meiotic phase as it occurs after mitosis or meiosis respectively. Further, it is also called the pre-synthetic phase as it occurs before the S-phase or synthesis phase.