AP BiologyCommon mistakesA resting cell sits in G0, outside the cycle

A resting cell sits in G0, outside the cycle

  1. The idea
  2. Predict
  3. See it
  4. Why
  5. Check

The idea

“A cell that isn't dividing is paused partway through the cycle, like in G2.”

The cycle is drawn as a loop, so it's easy to picture every cell on it. A cell waiting in G2 even sounds like it's resting.

The short version

The mistake: A cell that isn't dividing is paused partway through the cycle, like in G2.

What's actually true: A cell that stops dividing usually leaves the cycle from G1 and rests in G0, before its DNA is copied.

  1. Every phase after G1 is a step toward dividing.
  2. A cell that stops dividing usually leaves the cycle from G1, before S, and enters G0. It still does its job there, like making bile.
  3. Without growth factors, a cell usually doesn't pass the G1 checkpoint and moves into G0. It has no half-copied DNA to finish, so it can stay there for years.

On the exam: A cell that isn't dividing usually rests in G0, before its DNA is copied.

Every common AP Biology mistake