In a Meristematic cell, DNA quantity becomes double in

Options

A. `G_(1)`-sub phase
B. S-sub phase
C. `G_(2)`-sub phase
D. Prophase

Answer

To determine when the DNA quantity becomes double in a meristematic cell, we need to analyze the different phases of the cell cycle. Here's a step-by-step solution:

### Step-by-Step Solution:

1. **Understand the Cell Cycle Phases**: The cell cycle consists of interphase (which includes G1, S, and G2 phases) and the mitotic phase (M phase).

2. **Identify the Phases**:
- **G1 Phase**: This is the first gap phase where the cell grows and carries out normal functions. There is no DNA replication during this phase.
- **S Phase**: This is the synthesis phase where DNA replication occurs. Each chromosome is duplicated, resulting in double the amount of DNA.
- **G2 Phase**: This is the second gap phase where the cell prepares for mitosis. The DNA has already been replicated in the S phase, so there is no further doubling of DNA in this phase.
- **Prophase**: This is a stage of mitosis where the chromosomes condense and become visible. The DNA has already been replicated by this point.

3. **Analyze Each Option**:
- **G1 Subphase**: No DNA replication occurs here. (Incorrect)
- **S Subphase**: This is where DNA synthesis occurs, and the quantity of DNA doubles. (Correct)
- **G2 Subphase**: The DNA is already doubled from the S phase; no further doubling occurs. (Incorrect)
- **Prophase**: This is part of mitosis, and the DNA has already been replicated. (Incorrect)

4. **Conclusion**: The correct answer is the S subphase, as this is the phase where the DNA quantity becomes double in a meristematic cell.

### Final Answer:
In a meristematic cell, the DNA quantity becomes double in the **S subphase**.

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