In which phase of a cell cycle does the DNA replication take place?

Options

A. Prophase
B. S phase
C. G1 phase
D. G2 phase

Answer

**Step-by-Step Solution:**

1. **Understanding the Cell Cycle**: The cell cycle consists of several phases, including G1 (Gap 1), S (Synthesis), G2 (Gap 2), and M (Mitosis).

2. **Identifying the Phases**:
- **G1 Phase**: This is the first phase after cell division where the cell grows and prepares for DNA synthesis.
- **S Phase**: This is the phase where DNA replication occurs. Each chromosome is duplicated to ensure that the daughter cells will have the same genetic material.
- **G2 Phase**: After DNA replication, the cell continues to grow and prepares for mitosis. RNA and protein synthesis occurs here.
- **M Phase**: This is the phase where the cell divides into two daughter cells.

3. **Focusing on DNA Replication**: The question specifically asks about DNA replication. This process is crucial for ensuring that each daughter cell receives an identical set of chromosomes.

4. **Conclusion**: Based on the understanding of the cell cycle phases, DNA replication occurs specifically in the **S Phase**.

**Final Answer**: DNA replication takes place in the S phase of the cell cycle.

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