Question

During which phase(s) of the cell cycle, the amount of DNA in a cell remains at the 4C level if the initial amount is denoted as 2C?

• A. $G_0$ and $G_1$
• B. $G_1$ and S
• C. Only $G_2$
• D. $G_2$ and M

Answer 1

The correct option is C Only $G_2$

A cell cycle is divided into $G_1$, S, $G_2$ and M phases. $G_1$ or first growth is followed by S phase or synthesis phase. DNA replication occurs in S phase and DNA amount doubles up, i.e., a cell with 2C DNA in $G_1$ phase will now have 4C DNA. $G_2$ phase is second growth phase where the DNA content remains the same 4C. M phase is the phase of division where DNA content either regains 2C level (mitosis) or becomes halved, i.e., 1C (in meiosis). $G_0$ phase is the phase of differentiation where the cell contains DNA in the same amount as its parent cell and does not divide further.