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

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

Answer: (D)

Verified step by step guidance

1. Understand the phases of the eukaryotic cell cycle: G1 phase (first gap), S phase (DNA synthesis), G2 phase (second gap), and M phase (mitosis).
2. Recall that the G1 phase is the period after cell division and before DNA replication, where the cell grows and performs normal functions.
3. Recognize that the S phase is when DNA replication occurs, which is a relatively fixed duration.
4. Note that the G2 phase is a short period of preparation for mitosis, and the M phase is the process of cell division itself, both generally shorter than G1.
5. Conclude that the G1 phase is typically the longest phase because the cell spends most of its time growing and preparing for DNA synthesis.