Optometry Admission Test (OAT) Practice

What occurs during the S stage of cell division?

1. Cell division occurs

2. Organelle replication happens

3. DNA replication takes place

4. Cytoplasm doubles in size

The correct answer is: DNA replication takes place

During the S stage of the cell cycle, which stands for synthesis, DNA replication occurs. This is a critical phase where the genetic material of the cell is duplicated, ensuring that when the cell divides, each daughter cell will receive an identical set of chromosomes. The importance of DNA replication during this stage cannot be overstated, as it sets the foundation for proper cell function and genetic fidelity in subsequent generations of cells. This process involves the unwinding of the double helix, and the synthesis of new strands by DNA polymerase, ultimately leading to two identical copies of each chromosome. While organelle replication happens in the cell cycle at other stages, it is not the primary focus of the S stage. Similarly, while cell division and cytoplasmic changes do occur in the overall cell cycle, these processes are associated with different stages, specifically mitosis and cytokinesis, rather than the DNA synthesis that exclusively defines the S phase.