In a typical proliferating eukaryotic cell, which phase is generally the longest portion of the cell cycle?

• A. M phase (mitosis and cytokinesis)
• B. G2 phase
• C. S phase
• D. Interphase

Answer: (D)

Verified step by step guidance

1. Understand the overall structure of the eukaryotic cell cycle, which consists of interphase and the M phase. Interphase includes G1, S, and G2 phases, while M phase includes mitosis and cytokinesis.
2. Recall that interphase is the period when the cell grows, duplicates its DNA, and prepares for mitosis, whereas M phase is the actual process of cell division.
3. Identify the durations of each phase: G1 is the first gap phase, S is the synthesis phase where DNA replication occurs, G2 is the second gap phase, and M phase is relatively short compared to interphase.
4. Recognize that interphase (G1 + S + G2) collectively takes up the majority of the cell cycle time, making it the longest portion of the cycle.
5. Conclude that since interphase encompasses most of the cell's preparation and growth activities, it is generally the longest phase in a proliferating eukaryotic cell.