Cell cycle phase duration calculation

Steps:

• Convert total cycle time to minutes: 1.75 hours × 60 = 105 minutes.
• Analyze diagram for phase timelines; cell growth (G1) spans the initial segment equaling 5.2 minutes.
• Compare 5.2 minutes to other phases: DNA synthesis (S) is longer, mitosis (M) shorter.
• Confirm cell growth phase matches the 5.2-minute duration.

Why A is correct:

• Cell growth (interphase G1) precedes DNA synthesis and constitutes the diagram's early phase timed at 5.2 minutes per the cell cycle model.

Why the others are wrong:

• B: Cytoplasm divides (cytokinesis) occurs post-mitosis, lasting under 1 minute in the diagram.
• C: DNA synthesis (S phase) takes about 30-40 minutes, far exceeding 5.2 minutes.
• D: Nucleus divides (mitosis) spans 10-15 minutes in the diagram's final stage.

Final answer: A