The subphase of prophase-I showing disintegration of nuclear membrane and nucleoli respectively are

Options

A. Leptotene, Zygotene
B. Zygotene, Pachytene
C. Zygotene, Diplotene
D. Diakinesis, Diplonema

Answer

To answer the question regarding the subphase of prophase-I during which the nuclear membrane and nucleoli disintegrate, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Meiosis**: Meiosis is a type of cell division that reduces the chromosome number by half, resulting in four haploid cells. It consists of two main stages: Meiosis I and Meiosis II.

2. **Identifying Prophase I**: Prophase I is the first stage of Meiosis I and is the longest phase of meiosis. It is characterized by several key events, including chromatin condensation, homologous chromosome pairing, and crossing over.

3. **Subphases of Prophase I**: Prophase I is divided into five subphases:
- Leptonema
- Zygonema
- Pachynema
- Diplonema
- Diakinesis

4. **Disintegration of Nuclear Membrane and Nucleoli**:
- During **Diplonema**, the synaptonemal complex begins to dissolve, and the chromosomes start to separate. This is when the nuclear membrane starts to disintegrate.
- During **Diakinesis**, the nuclear envelope and nucleoli completely disintegrate, and the chromosomes further condense, preparing for metaphase.

5. **Conclusion**: The subphases of prophase I where the nuclear membrane and nucleoli disintegrate are **Diplonema** (for the initial disintegration) and **Diakinesis** (for the complete disintegration).

### Final Answer:
The subphases of prophase-I showing disintegration of the nuclear membrane and nucleoli are **Diplonema** and **Diakinesis**.

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