Question

During cell growth, DNA synthesis takes place in
A.$G_2$ phase
B.M phase
C.S phase
D.$G_1$ phase

Answer 1

Hint: Cell cycle is a series of events that occur in a cell when a cell prepares itself for cell dicion. It is a four stage process which consists of M phase, $G_1$, $G_2$ and S phase.

Complete answer:
For the cells to divide into two equal halves the genetic material of the cell has to be divided to. But for the genetic material to divide equally, two copies of genetic material has to be synthesised. DNA occurs during the cell cycle. Let us analyze the options to find out the correct answer.

Option A: $G_2$ phase is the Gap 2 phase of the interphase. It is a gap between the S phase and the M phase. It is a checkpoint which decides whether the cell will grow further and is ready to enter the M phase of the cell cycle. Therefore, this is the incorrect option.

Option B: M phase is the phase of the cell cycle in which meiosis or mitosis occur. At this point, cell growth stops and division of the daughter cells and all the contents of the cells into two halves occur. The Metaphase checkpoint in the middle ensures everything is normal and the cell is now ready to divide. Therefore, this is the incorrect option.

Option C: S phase is the phase of cell cycle where synthesis of genetic material that is DNA synthesis takes place. DNA replicates and forms two copies. Therefore, this is the correct option.

Option D: $G_1$ phase is the phase of interphase in which the cell increases in its size and checkpoint ensures that everything is ready for the cell to proceed to S phase. Therefore, this is the incorrect option.

Hence, the correct answer is option (C)

Note: 1.Interphase of the cell cycle is divided into $G_1$ phase, S phase and $G_2$ phase.
2.M phase consists of prophase, metaphase, anaphase and telophase.