A Level Biology Practice Exam

Which of the following best describes the G1 phase of interphase?

1. DNA synthesis

2. Cell division

3. Cell growth and normal function

4. Preparation for mitosis

The correct answer is: Cell growth and normal function

The G1 phase of interphase is primarily characterized by cell growth and the normal functioning of the cell. During this phase, the cell increases in size, synthesizes mRNA and proteins that are essential for DNA replication, and carries out its normal metabolic functions. This phase is critical because it sets the stage for the subsequent stages of the cell cycle, ensuring that the cell has the necessary components to replicate its DNA in the synthesis phase. The other options do not accurately describe the G1 phase. DNA synthesis occurs in the S phase of interphase, while cell division takes place during the mitotic phase of the cell cycle. The preparation for mitosis is associated with the G2 phase, where the cell ensures it is ready to divide by checking DNA integrity and synthesizing proteins necessary for mitosis. Hence, the best description of the G1 phase is indeed focused on cell growth and its normal functionality.