Shape of the chromosome is determined by :
(a) Telomere
(b) Centromere
(c) Chromomere
(d) Centrosome

Options

A. Telomere
B. Centromere
C. Chromomere
D. Centrosome

Answer

To determine the shape of a chromosome, we need to understand the roles of various components of the chromosome. Let's analyze the options provided in the question step by step.

### Step-by-Step Solution:

1. **Understanding Chromosome Structure**:
- A chromosome is a condensed structure that contains genetic material. It consists of two sister chromatids joined together at a specific region.

2. **Identifying the Key Components**:
- The main components of a chromosome include:
- **Telomere**: The protective end of a chromosome.
- **Centromere**: The region where the two sister chromatids are joined together.
- **Chromomere**: Localized constrictions along the chromosome.
- **Centrosome**: An organelle that serves as the main microtubule organizing center, not directly involved in chromosome shape.

3. **Role of the Centromere**:
- The centromere is crucial for the structural integrity of the chromosome. It holds the sister chromatids together and plays a significant role in the movement of chromosomes during cell division.
- The position of the centromere affects the overall shape of the chromosome:
- **Metacentric**: Centromere in the middle, arms are equal.
- **Sub-metacentric**: Centromere slightly off-center, arms are unequal.
- **Acrocentric**: Centromere closer to one end, one arm is significantly shorter.
- **Telocentric**: Centromere at the terminal end.

4. **Conclusion**:
- Based on the analysis, the shape of the chromosome is primarily determined by the position of the centromere. Therefore, the correct answer is **(b) Centromere**.

### Final Answer:
(b) Centromere