The part of chromosome at primary constriction area is called

Options

A. Kinetochore
B. Centromere
C. Chromatin
D. Nucleus

Answer

To answer the question "The part of chromosome at primary constriction area is called," we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Chromosomes**:
- Chromosomes are structures found in the nucleus of eukaryotic cells. They are made up of chromatin, which is a complex of DNA and proteins.

2. **Identifying the Primary Constriction**:
- Within each chromosome, there is a specific region known as the primary constriction. This is where the two sister chromatids are joined together.

3. **Defining the Primary Constriction**:
- The primary constriction of a chromosome is referred to as the **centromere**. It plays a crucial role during cell division, as it is the point where the spindle fibers attach to pull the chromatids apart.

4. **Kinetochore**:
- Associated with the centromere is a protein structure called the **kinetochore**, which is essential for the movement of chromosomes during cell division. However, it is not the primary constriction itself.

5. **Conclusion**:
- Therefore, the part of the chromosome at the primary constriction area is called the **centromere**.

### Final Answer:
The part of chromosome at the primary constriction area is called the **centromere**.

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