During cell division, centriole duplication takes place in :-

Options

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

Answer

**Step-by-Step Solution:**

1. **Understanding Cell Division Phases:**
The cell cycle consists of several phases: G1 (first growth phase), S (synthesis phase), G2 (second growth phase), and M (mitotic phase). Each phase has specific functions related to cell growth and division.

2. **Identifying the Role of Centrioles:**
Centrioles are cylindrical structures that play a crucial role in cell division by organizing microtubules to form the spindle fibers, which are essential for chromosome segregation.

3. **Locating Centriole Duplication:**
Centriole duplication occurs specifically during the S phase of the cell cycle. During this phase, the cell synthesizes DNA and duplicates its centrioles.

4. **Formation of Procentrioles:**
In the S phase, new centrioles, known as procentrioles, begin to form at the proximal end of each parental centriole. This is a critical step in preparing the cell for mitosis.

5. **Conclusion:**
After analyzing the phases and the role of centrioles, we conclude that centriole duplication takes place in the S phase of the cell cycle.

**Final Answer:**
Centriole duplication takes place in the **S phase** of the cell cycle.

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