Question

A model of the cell cycle is shown here. Based on your knowledge of the cell cycle and the percentage of cells in each stage of the cell cycle, evaluate each of the following statements. Select THREE correct options.
Responses
A 90% of the time the cell is in interphase.90% of the time the cell is in interphase.
B Mitosis is the longest phase of the cell cycle.Mitosis is the longest phase of the cell cycle.
C 10% of the time, the cell is dividing its nucleus and cytoplasm.10% of the time, the cell is dividing its nucleus and cytoplasm.
D The cell spends more than half of its time growing in size and duplicating organelles.The cell spends more than half of its time growing in size and duplicating organelles.
E The cell spends 5X more time duplicating the DNA compared to dividing the nuclear components.

Answer 1

Correct answers: A, C, D.

Brief explanations:
- A (true): Interphase (G1 + S + G2) makes up about 90% of the cycle in the model, so the cell spends ~90% of its time in interphase.
- C (true): Mitosis (including cytokinesis) is ~10% of the cycle in the model, so ~10% of the time the cell is dividing nucleus and cytoplasm.
- D (true): Growth and organelle duplication occur mainly in G1 (and some preparation in G2); G1+G2 together are more than half of the cycle in the model, so the cell spends >50% of its time growing/duplicating organelles.

Why B and E are false:
- B is false because mitosis is one of the shortest phases (~10%), not the longest.
- E is false because DNA replication (S phase) is not five times as long as mitosis in the model (S is only a few times longer than M, not 5×).