Question

In which stage DNA replication takes place?

• A. Metaphase
• B. $G_1$ -phase
• C. $S$- phase
• D. $G_2$ -phase

Answer 1

The correct option is C $S$- phase

The $G_1$ phase is the gap between M phase and S phase and is marked by synthesis of RNA and protein (excluding histones) and duplication of all cell content except DNA.

S phase of DNA replication is followed by $G_2$ phase during which cell double-checks the duplicated DNA content.

The M phase of cell cycle is marked by the division of the nucleus and cytokinesis to produce daughter cells. $G_0$ phase is the quiescent stage.

So, the correct answer is S - phase.