Advanced Placement (AP) Biology Practice Exam

What is the result of a cell exiting the G1 phase?

1. The cell undergoes apoptosis

2. The cell begins synthesizing DNA

3. The cell remains in a nondividing state

4. The cell starts to divide immediately

The correct answer is: The cell remains in a nondividing state

When a cell exits the G1 phase of the cell cycle, it enters the S phase, where DNA synthesis occurs. The G1 phase is primarily focused on cell growth and preparation for DNA replication. After G1, the cell will undergo a transition to the S phase, which is crucial for duplicating the genetic material in preparation for cell division. Thus, stating that the cell remains in a nondividing state does not reflect the progression expected after G1. The correct understanding is that exiting G1 typically means that the cell is poised to move into the next logical phase, the S phase, leading towards division. The other options reflect various outcomes that do not accurately describe the normal sequence of events following the G1 phase exit, such as apoptosis, which is programmed cell death, and immediate cell division, which does not occur until the cell completes additional necessary phases of the cell cycle.