Given a diagram of the eukaryotic cell cycle labeled with letters, which phase does the letter 'C' most likely represent?

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

Answer: (C)

Verified step by step guidance

1. Understand the eukaryotic cell cycle, which consists of four main phases: G1 (Gap 1), S (Synthesis), G2 (Gap 2), and M (Mitosis). These phases occur in a specific sequence to ensure proper cell growth and division.
2. Recall the key characteristics of each phase: G1 is the phase where the cell grows and performs normal functions, S is the phase where DNA replication occurs, G2 is the phase where the cell prepares for mitosis, and M is the phase where the cell divides.
3. Analyze the diagram provided. If the letter 'C' corresponds to the phase where DNA replication occurs, it is most likely the S phase. DNA replication is a defining feature of the S phase.
4. Cross-check the other options: M phase involves cell division, G1 phase involves cell growth and normal function, and G2 phase involves preparation for mitosis. None of these match the description of DNA replication.
5. Conclude that the letter 'C' most likely represents the S phase, as it is the phase where DNA synthesis (replication) occurs, which is a critical step in the cell cycle.