Total number of peripheral microtubules in flagella is (i) and in centrioles is (ii) .

Options

A. (i)-18, (ii)-27
B. (i)-27, (ii)-18
C. (i)-20, (ii)-27
D. (i)-27, (ii)-20

Answer

To solve the question regarding the total number of peripheral microtubules in flagella and centrioles, we can break down the information as follows:

### Step 1: Understanding Flagella Structure
- Flagella are composed of microtubules arranged in a specific pattern known as the "9 + 2" arrangement.
- This means there are 9 pairs of peripheral microtubules and 2 central microtubules.

### Step 2: Calculating Peripheral Microtubules in Flagella
- Since there are 9 pairs of peripheral microtubules, the total number of peripheral microtubules in flagella is:
\[ 9 \times 2 = 18 \]

### Step 3: Understanding Centrioles Structure
- Centrioles are cylindrical structures made up of microtubules.
- Each centriole has a total of 27 peripheral microtubules arranged in a specific pattern.

### Step 4: Conclusion
- Therefore, the total number of peripheral microtubules in flagella is 18 (i), and in centrioles is 27 (ii).

### Final Answer:
- (i) 18 peripheral microtubules in flagella
- (ii) 27 peripheral microtubules in centrioles

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