In eukaryotic cells, DNA replication occurs during which phase of the cell cycle?

• A. G1 phase of interphase
• B. M phase (mitosis)
• C. S phase of interphase
• D. G2 phase of interphase

Answer: (C)

Verified step by step guidance

1. Understand the phases of the eukaryotic cell cycle: G1 phase (cell growth), S phase (DNA synthesis), G2 phase (preparation for mitosis), and M phase (mitosis).
2. Recall that DNA replication specifically refers to the process of copying the entire genome to ensure each daughter cell receives a complete set of chromosomes.
3. Identify which phase is responsible for DNA synthesis by remembering that the 'S' in S phase stands for 'Synthesis,' indicating DNA replication occurs here.
4. Recognize that during G1 and G2 phases, the cell is preparing for DNA replication and mitosis, but the actual replication does not occur in these phases.
5. Conclude that DNA replication occurs during the S phase of interphase, which is the phase dedicated to synthesizing a complete copy of the cell's DNA.