A microtubule has a diameter of

Options

A. `100 Ã…`
B. `150 Ã…`
C. `250 Ã…`
D. 100 nm

Answer

To solve the question regarding the diameter of a microtubule, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Structure of Microtubules**:
Microtubules are cylindrical structures made up of tubulin protein polymers. They are a key component of the cytoskeleton in eukaryotic cells.

2. **Identify the Common Characteristics**:
A typical microtubule is composed of 13 protofilaments arranged in a tubular structure.

3. **Determine the Diameter**:
The average diameter of a microtubule is generally reported to be around 25 nanometers.

4. **Convert Units if Necessary**:
Since the question provides options in angstroms, we need to convert nanometers to angstroms.
- 1 nanometer = 10 angstroms.
- Therefore, 25 nanometers = 25 x 10 = 250 angstroms.

5. **Evaluate the Options**:
The options given are:
- 100 angstrom
- 150 angstrom
- 250 angstrom
- 100 nanometer

From our calculations, we see that 250 angstroms is the correct answer as it matches the diameter of a microtubule.

6. **Select the Correct Answer**:
The correct answer to the question is **250 angstrom**.

### Final Answer:
The diameter of a microtubule is **250 angstrom**.

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