Scientists determined the total mass of DNA from a sample of animal cells. The masses of equal numbers of cells were taken during three different stages of the cell cycle. Stage I contains cells massed during G1 of the cell cycle.

Question

Which statement best describes the cells during Stage II?
A. The cells have replicated their DNA, but have not completed mitosis and cytokinesis.
B. The cells have completed mitosis and cytokinesis without replicating their DNA.
C. The cells have replicated their DNA and completed mitosis and cytokinesis.
D. The cells have temporarily exited the cell cycle without replicating their DNA.

Answer 1

The best statement that describes the cells during Stage II is:

A. The cells have replicated their DNA, but have not completed mitosis and cytokinesis.

In the context of the cell cycle, Stage I (G1 phase) refers to the phase where the cell is growing and preparing to duplicate its DNA. In Stage II, which corresponds to the S phase, the DNA is replicated, but the cell has not entered mitosis (M phase) yet, where it would complete cell division through mitosis and cytokinesis.