Question

During cell growth, DNA synthesis takes place in

• A. $G_2$ phase
• B. M pahse
• C. S phase
• D. $G_1$ phase

Answer 1

Answer: (C)

S phase

• Interphase is the period between two subsequent M phases and consists of three phases: $G_1$, S phase (the period of DNA replication) and $G_2$ 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 and cell division is followed by $G_2$ phase during which cell double-checks the duplicated DNA content.
  

Therefore, the correct answer is option C.