During which phase of interphase does the DNA content double compared to the original cell?

• A. S phase
• B. G1 phase
• C. G2 phase
• D. M phase

Answer: (A)

Verified step by step guidance

1. Understand the cell cycle: The cell cycle consists of interphase and the mitotic phase. Interphase is further divided into three phases: G1, S, and G2.
2. Identify the role of each interphase phase: G1 phase is the first gap phase where the cell grows and performs normal functions. S phase is the synthesis phase where DNA replication occurs. G2 phase is the second gap phase where the cell prepares for mitosis.
3. Focus on DNA replication: During the S phase, the cell replicates its DNA, resulting in the doubling of the DNA content compared to the original cell.
4. Compare the phases: In the G1 phase, the cell grows but does not replicate DNA. In the G2 phase, the cell has already doubled its DNA content during the S phase and is preparing for mitosis.
5. Conclude which phase doubles the DNA content: Since DNA replication occurs during the S phase, this is the phase where the DNA content doubles compared to the original cell.