Tetrad is made of

Options

A. Four homologous chromosomes with four chromatids
B. Two homologous chromosomes, each with two chromatids
C. Four non-homologous chromatids
D. Four non-homologous chromosomes

Answer

**Step-by-Step Solution:**

1. **Understanding the Term "Tetrad":**
- The term "tetrad" is derived from the Greek word "tetra," which means four. In the context of cell division, particularly during meiosis, a tetrad refers to a structure that consists of four chromatids.

2. **Identifying Chromatids in Meiosis:**
- During meiosis, specifically in the prophase stage, homologous chromosomes pair up. Each chromosome consists of two sister chromatids. Therefore, when two homologous chromosomes come together, they form a tetrad, which contains a total of four chromatids.

3. **Phases of Meiosis:**
- The formation of tetrads occurs during the zygotene stage of prophase I of meiosis. This is where homologous chromosomes align closely together and begin to pair up.

4. **Characteristics of Tetrads:**
- A tetrad consists of two homologous chromosomes, each made up of two sister chromatids. Thus, the tetrad is made up of four chromatids in total.

5. **Conclusion:**
- Therefore, a tetrad is made of **four chromatids** that are formed from the pairing of **two homologous chromosomes** during the zygotene phase of meiosis.

**Final Answer:**
A tetrad is made of **four chromatids** (two homologous chromosomes, each with two sister chromatids).

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