During synapsis, the number of chromonemata /DNA in bivalent chromosome are

Options

A. 2
B. 4
C. 8
D. 16

Explanation

To solve the question regarding the number of chromonemata/DNA in bivalent chromosomes during synapsis, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Bivalent Chromosomes**:
- A bivalent chromosome consists of two homologous chromosomes that are paired together during meiosis. Each homologous chromosome is made up of two sister chromatids.

2. **Identifying Chromonemata**:
- Chromonemata refer to the individual strands of DNA within a chromosome. In the context of a bivalent chromosome, each chromatid is considered a chromonema.

3. **Counting Chromonemata in Bivalents**:
- Since each homologous chromosome has two sister chromatids, a bivalent (which consists of two homologous chromosomes) will have a total of four chromonemata. This is calculated as follows:
- 2 homologous chromosomes × 2 sister chromatids each = 4 chromonemata.

4. **Conclusion**:
- Therefore, during synapsis, the number of chromonemata in a bivalent chromosome is **4**.

### Final Answer:
The number of chromonemata/DNA in bivalent chromosomes during synapsis is **4**.

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