Question

In which of the following phase DNA / chromosome replication takes place?

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

Answer 1

Answer: (C)

S-phase

• The cell cycle consists of 2 phases, the mitotic phase, and interphase.
• The interphase is divided into the first growth phase (G${}_1$phase), synthesis phase (S phase) and second growth phase (G${}_2$ phase). G${}_1$ (Gap 1) is the phase where a large amount of protein synthesis occurs required for the DNA replication and the volume of the cytoplasm increases.

• The S phase stands for the synthesis phase in which DNA replication occurs followed by synthesis of histones. G${}_2$ phase is a period of rapid cell growth and protein synthesis, during which the cell prepares itself for mitosis.

Thus, the correct answer is option C.