Arrangement of microtubules in centriole is :-

Options

A. 9 + 2
B. 2 + 9
C. 11 + 0
D. 9 + 0

Answer

**Step-by-Step Solution:**

1. **Understanding Centrioles**: Centrioles are cylindrical structures found in the centrosome of a cell. They play a crucial role in cell division and organization of microtubules.

2. **Microtubule Arrangement**: The arrangement of microtubules in centrioles is characterized as a "9 plus 0" arrangement. This means that there are 9 triplet microtubules arranged in a circular pattern, with no central pair of microtubules.

3. **Comparison with Cilia**: It is important to differentiate this from the "9 plus 2" arrangement, which is found in cilia and flagella. In the "9 plus 2" arrangement, there are 9 doublet microtubules surrounding 2 central microtubules.

4. **Centriole Structure**: Each centriole consists of a cartwheel-like structure made up of these 9 peripheral microtubule triplets. They are evenly spaced and arranged perpendicular to each other.

5. **Pericentriolar Material**: Centrioles are surrounded by amorphous pericentriolar material, which helps in the organization and anchoring of microtubules.

6. **Conclusion**: Therefore, the arrangement of microtubules in a centriole is specifically described as a "9 plus 0" arrangement.