Question

Students in a biology lab isolated cells in various phases of the cell cycle. A population of cells that has 1 1/2 × the DNA of G1 phase cells was most likely isolated from which of the following parts of the cell cycle?

a) G1 phase
b) S phase
c) G2 phase
d) M phase

Answer 1

A population of cells with 1 1/2 times the DNA of G1 phase cells is most likely in the S phase of the cell cycle, as this is when DNA synthesis occurs, leading to an increase in DNA content before it doubles.

Step-by-step explanation:

The student's question pertains to the identification of a cell population with 1 1/2 × the DNA of G1 phase cells and which phase of the cell cycle they are most likely to be in. During the G1 phase, cells grow and carry out normal metabolic functions, preparing for DNA replication, but DNA content does not change. The S phase is characterized by DNA replication, resulting in an increase in the cellular DNA content. Following this, the G2 phase involves further growth, and the DNA content remains constant but is double that of the G1 phase. Since the population of cells in question has 1 1/2 times the DNA of G1 phase cells, they are most likely in the S phase, where DNA synthesis is actively occurring, and DNA content is steadily increasing up to the point of duplication.