OCR General Certificate of Secondary Education (GCSE) Biology Practice Exam

What occurs during 'gap phase one' in the cell cycle?

1. The cell replicates its DNA

2. The cell grows and new structures are formed

3. The cell divides into two identical cells

4. The DNA forms into chromosomes

The correct answer is: The cell grows and new structures are formed

During 'gap phase one' (G1) of the cell cycle, the primary activity is cell growth and the synthesis of new proteins and organelles. This phase is crucial for preparing the cell for DNA replication, which will occur in the subsequent phase (S phase). Throughout G1, the cell undergoes metabolic processes that ensure it has the necessary components and energy reserves to duplicate its DNA and ultimately divide. In this phase, the cell not only increases in size but also synthesizes RNA and produces proteins necessary for DNA synthesis and other functions. This growth contributes to the overall health and functionality of the cell before it commits to division. While the other processes listed—such as DNA replication, cell division, and chromosome formation—are critical parts of the cell cycle, they occur in different phases. DNA replication takes place in S phase, cell division happens in the M phase, and chromosome condensation is part of prophase during mitosis. Thus, the essential activity during gap phase one is the growth and formation of new structures in preparation for future phases.