In which stage of cell cycle nucleus becomes bigger :-

Options

A. `G_(1)`
B. `G_(2)`
C. S
D. M

Answer

**Step-by-Step Text Solution:**

1. **Understanding the Cell Cycle**: The cell cycle consists of several stages: G1 phase, S phase, G2 phase, and M phase. Each stage has specific functions and activities related to cell growth and division.

2. **Evaluating the G1 Phase**: The G1 phase is the first stage of interphase where the cell grows and synthesizes proteins. While the cell is increasing in size, the nucleus does not significantly increase in size during this phase. Therefore, G1 phase is not the correct answer.

3. **Evaluating the S Phase**: The S phase, or Synthesis phase, is where DNA replication occurs. During this phase, the genetic material is duplicated, which leads to an increase in the size of the nucleus as it contains the replicated DNA. This is the key phase where the nucleus becomes bigger.

4. **Evaluating the G2 Phase**: The G2 phase is the second gap phase where the cell prepares for mitosis. Although the cell continues to grow and synthesize proteins, the nucleus does not significantly increase in size during this phase. Thus, G2 phase is also not the correct answer.

5. **Evaluating the M Phase**: The M phase, or mitotic phase, is when the cell divides into two daughter cells. During this phase, the nucleus divides, but it does not increase in size. Therefore, M phase is not the correct answer.

6. **Conclusion**: Based on the evaluations, the correct answer is the S phase, where the nucleus becomes bigger due to DNA replication.

**Final Answer**: The nucleus becomes bigger during the S phase of the cell cycle.

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