In axoneme of cilia how many radially arranged peripheral doublet of microtubules are present?

Answer

To solve the question about the number of radially arranged peripheral doublets of microtubules present in the axoneme of cilia, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Structure of Cilia**:
- Cilia are hair-like structures that extend from the surface of many eukaryotic cells. They play a role in movement and sensory functions.
- The core structure of a cilium is known as the axoneme.

2. **Identifying the Components of the Axoneme**:
- The axoneme consists of microtubules arranged in a specific pattern.
- In the axoneme, there are central tubules and peripheral doublets.

3. **Counting the Peripheral Doublets**:
- In the axoneme of cilia, there are **9 peripheral doublets** of microtubules arranged radially around the central pair of microtubules.
- Each doublet consists of two microtubules.

4. **Understanding the Arrangement**:
- This arrangement is often referred to as the "9 + 2" structure, where "9" refers to the peripheral doublets and "2" refers to the central pair of microtubules.

5. **Conclusion**:
- Therefore, the total number of radially arranged peripheral doublets of microtubules present in the axoneme of cilia is **9**.

### Final Answer:
**There are 9 radially arranged peripheral doublets of microtubules in the axoneme of cilia.**