Question

Which one is Correct regarding Somatic Cell cycle?
a) G$2$- phase follows mitotic phase.
b) In $G1$-phase DNA content is double the amount of DNA present in the original cell.
c) DNA replication occurs in S-phase.
d) A short phase is followed by a long mitotic phase.

Answer 1

A somatic cell is the informal term for a body cell, except for the reproductive cells that are-sperm and ovum. Except that, all other cells present in the human body are referred to as somatic cells. The somatic cell cycle has-two phases- interphase and mitotic phase. In the interphase the DNA gets replicated and the cellular growth happens.

Complete answer:
c) DNA replication occurs in S-phase. – During the synthetic phase also known as Interphase, the DNA replication occurs and the cells start to divide. Interphase is subdivided into S, G$1$ and G$2$ phase.
Hence, option C is the correct answer.

a) G$2$- phase follows mitotic phase- this option is not applicable because replication can only take place in S phase of interphase.
Option A is not the correct answer.
b) In $G1$-phase DNA content is double the amount of DNA present in the original cell- in G$1$ phase, the content of the cell grows and the volume of organelles along with protein doubles.
Option B is not the correct answer.
d) A short phase is followed by a long mitotic phase- in the gap phase, cells increase in size then followed by mitotic or M phase.
Option D is not correct.

Note:
The wholesome DNA gets synthesis during the cell and the genetic content gets a $4$N complement of DNA at its end. There are checkpoints to ensure that the cell cycle is not reversible or going in the right direction or not. There are protein kinases like- RAD$53$ which respond to DNA damage.