A cell in G2 of the cell division cycle contains 20 chromatids.How many centromeres are present in this cell?
A)10
B)20
C)30
D)40
E)80

Question

Quizplus · Accepted Answer

In the G2 phase of the cell cycle, each chromosome has already been replicated into two sister chromatids, but they are still joined together at a common centromere. Therefore, if there are 20 chromatids, they would be organized into 10 pairs of sister chromatids, meaning there are 10 chromosomes each with one centromere. However, the question asks for the number of centromeres in a cell with 20 chromatids, not chromosomes. Since each chromatid is part of a chromosome and each chromosome has a centromere, there are 20 centromeres present to match the 20 chromatids.

A Cell in G2 of the Cell Division Cycle Contains