Advanced Placement (AP) Biology Practice Exam

During which phase does the cell undergo the second growth phase?

1. G0 phase

2. G1 phase

3. G2 phase

4. M phase

The correct answer is: G2 phase

The second growth phase of the cell cycle is the G2 phase. During G2, the cell has already completed DNA synthesis in the S phase and is preparing for mitosis. In this phase, the cell continues to grow and produce proteins while also ensuring that all the DNA has been accurately replicated and that any necessary repairs are made. Biologically, this phase is critical because it allows the cell to accumulate the necessary components, such as organelles and energy reserves, needed for successful cell division. The G2 phase acts as a checkpoint to verify that the cell is ready to enter mitosis, ensuring that division occurs only if conditions are right and the genetic material is intact. The other phases mentioned do not represent the second growth phase: - The G0 phase refers to a resting or quiescent state where the cell has exited the cell cycle and is not actively preparing to divide. - The G1 phase is the first growth phase where the cell grows and synthesizes proteins necessary for DNA replication. - The M phase is the mitotic phase where actual division occurs, encompassing both mitosis and cytokinesis. Understanding these phases is vital for grasping how cells regulate growth and division, which is essential in processes like development, tissue repair