A group of cell biologists studied epithelial mammary cells to measure the amount of time that cells spent in each phase. Their observations are shown in the table below.

Question

Phase Average Time Spent in Phase (Hours)
G1 4.04
S 8.97
G2 6.52
M 0.8
Total 20.33

Their data show that cells spend less than 5 percent of their time in mitosis and more than 95 percent of their time in interphase. Similar patterns have been shown in epithelial cells for the retina and the cervix. In fact, mitosis consistently represents only a tiny percentage of the time needed for a complete cell cycle.

Based on the data, cells spend the majority of their time in interphase.

Which statement best explains why cells spend so much time in interphase?
A.Cell growth and DNA replication take far more time than cell division and require more steps.
B.Differentiating cells to perform specific tasks takes time because the organism needs to determine how many new cells it needs for each type of tissue.
C.Moving chromosomes is a slow process, and the cell needs to be accurate when splitting and assigning them.
D.Regulatory proteins act as checkpoints during interphase, but there are no checkpoints to slow down mitosis.

Answer 1

A. Cell growth and DNA replication take far more time than cell division and require more steps.

This statement best explains why cells spend so much time in interphase. During interphase, cells grow, replicate their DNA, and prepare for division, which involves multiple critical processes and checks to ensure that everything is ready for mitosis. Mitosis, on the other hand, is a much shorter process that primarily involves the separation of already replicated chromosomes.