In which phase of cell division is oocyte arrested ?

Options

A. anaphase II
B. prophase I
C. interphase
D. both prophase I and II

Answer

**Step-by-Step Solution:**

1. **Understanding Oocyte Development**: Oocytes, which are the female gametes, originate from oogonia. These oogonia undergo mitotic divisions to form primary oocytes.

2. **Meiotic Division Initiation**: The primary oocytes begin the first meiotic division before birth. However, they do not complete this division immediately.

3. **Arrest in Prophase I**: The primary oocytes are arrested in the prophase stage of meiosis, specifically at the diplotene stage of prophase I. This means that they remain in a dormant state until certain hormonal changes occur.

4. **Hormonal Influence**: The arrest lasts until puberty, when hormonal signals, particularly from follicle-stimulating hormone (FSH) and luteinizing hormone (LH), stimulate the oocytes to resume their development.

5. **Resumption of Meiosis**: Upon receiving the appropriate hormonal signals, the oocyte resumes meiosis and progresses to metaphase II, where it can be fertilized if sperm is present.

6. **Conclusion**: Therefore, the phase of cell division in which the oocyte is arrested is **prophase I**.

**Final Answer**: The oocyte is arrested in **prophase I** of meiosis.

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