Which phase of prophase-I represents the transition to metaphase I ?

Options

A. Diakinesis
B. Leptotene
C. Diplotene
D. Zygotene

Answer

To determine which phase of prophase I represents the transition to metaphase I, we need to understand the stages of prophase I in meiosis.

### Step-by-Step Solution:

1. **Understand 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. **Identify Phases of Meiosis I**: Each of these stages is further divided into four phases: prophase, metaphase, anaphase, and telophase.

3. **Focus on Prophase I**: Prophase I is unique to meiosis and is subdivided into five distinct stages:
- **Leptotene**: Chromosomes begin to condense and become visible.
- **Zygotene**: Homologous chromosomes pair up through a process called synapsis, forming a synaptonemal complex.
- **Pachytene**: Crossing over occurs, where segments of DNA are exchanged between homologous chromosomes.
- **Diplotene**: The homologous chromosomes begin to separate but remain connected at points called chiasmata.
- **Diakinesis**: The final stage of prophase I, where the chromosomes condense further, and the chiasmata terminalize, preparing the chromosomes for alignment during metaphase I.

4. **Identify the Transition Phase**: The transition from prophase I to metaphase I occurs at the end of diakinesis. This is when the chromosomes are fully condensed and ready to align at the metaphase plate.

5. **Conclusion**: Therefore, the phase of prophase I that represents the transition to metaphase I is **Diakinesis**.

### Final Answer:
The phase of prophase I that represents the transition to metaphase I is **Diakinesis**.

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