In 'S' phase of the cell cycle

Options

A. Amount of DNA is reduced to half in each cell
B. Amount of DNA doubles in each cell
C. Amount of DNA remains same in each cell
D. Chromosome number is increased

Answer

### Step-by-Step Solution:

1. **Understanding the Cell Cycle**: The cell cycle is a series of events that cells go through as they grow and divide. It consists of interphase and the mitotic (M) phase.

2. **Phases of Interphase**: Interphase is divided into three phases:
- **G1 Phase (Gap 1)**: The cell grows and synthesizes proteins necessary for DNA replication.
- **S Phase (Synthesis)**: This is where DNA replication occurs.
- **G2 Phase (Gap 2)**: The cell continues to grow and prepares for division.

3. **Focus on S Phase**: During the S phase, the amount of DNA in the cell doubles. Each chromosome is replicated, resulting in two sister chromatids for each chromosome, which are held together at the centromere.

4. **Analyzing the Options**:
- **Option 1**: Amount of DNA is reduced to half in each cell. (Incorrect)
- **Option 2**: Amount of DNA doubles in each cell. (Correct)
- **Option 3**: Amount of DNA remains the same in each cell. (Incorrect)
- **Option 4**: Chromosome number is increased. (Incorrect)

5. **Conclusion**: The correct answer is that the amount of DNA doubles in each cell during the S phase.

### Final Answer:
The correct option is: **Amount of DNA doubles in each cell.**

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