Which of the following is correct about phases of the cell cycle ?

Options

A. In `G_1` - phase , DNA content is double the amount of DNA present in the original cell.
B. DNA replication takes place in S - phase.
C. A short interphase is followed by a long mitotic phase.
D. `G_2` - phase follows mitotic phase.

Answer

To determine which statement is correct about the phases of the cell cycle, we need to analyze each option based on our understanding of the cell cycle phases: G1, S, G2, and M phase (mitosis).

### Step-by-Step Solution:

1. **Understanding the Cell Cycle**:
- The cell cycle consists of two main phases: Interphase and M phase (mitotic phase).
- Interphase is further divided into three phases: G1 (Gap 1), S (Synthesis), and G2 (Gap 2).

2. **Analyzing Each Option**:
- **Option 1**: "In G1 phase, DNA content is double the amount of DNA present in the original cell."
- This statement is **incorrect**. In the G1 phase, the cell has not yet replicated its DNA. The DNA content is the same as the original cell. DNA replication occurs in the S phase.

- **Option 2**: "DNA replication takes place in S phase."
- This statement is **correct**. The S phase is specifically designated for DNA replication, where the DNA content of the cell is doubled.

- **Option 3**: "A short interphase is followed by a long mitotic phase."
- This statement is **incorrect**. Interphase is actually the longest phase of the cell cycle, while the M phase (mitotic phase) is relatively short.

- **Option 4**: "G2 phase follows mitotic phase."
- This statement is **incorrect**. The G2 phase occurs after the S phase and before the M phase. The mitotic phase follows G2.

3. **Conclusion**:
- The only correct statement regarding the phases of the cell cycle is: **"DNA replication takes place in S phase."**

### Final Answer:
The correct statement about the phases of the cell cycle is: **"DNA replication takes place in S phase."**

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