During which phase of the cell cycle are the chromosomes duplicated?

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

Answer: (C)

Verified step by step guidance

1. Understand the cell cycle: The cell cycle consists of several phases that a cell goes through to divide and produce new cells. These phases include G1, S, G2, and M.
2. Identify the role of each phase: G1 phase is the first gap phase where the cell grows and prepares for DNA replication. S phase is the synthesis phase where DNA replication occurs. G2 phase is the second gap phase where the cell prepares for mitosis. M phase is the mitosis phase where cell division occurs.
3. Focus on the S phase: During the S phase, the cell's DNA is replicated. This means that each chromosome is duplicated to ensure that both daughter cells will have the same genetic material after cell division.
4. Recognize the importance of DNA replication: DNA replication is crucial because it ensures that each new cell receives an exact copy of the parent cell's DNA, maintaining genetic consistency across cell generations.
5. Conclude that chromosome duplication occurs during the S phase: Based on the understanding of the cell cycle, it is clear that chromosomes are duplicated during the S phase, as this is when DNA synthesis and replication take place.