Bacterial flagellum consists of all the following parts except :

Options

A. Filament
B. Microtubule
C. Hook
D. Basal body

Answer

**Step-by-Step Solution:**

1. **Understanding the Bacterial Flagellum**: The bacterial flagellum is a structure that enables bacteria to move. It is typically helical in shape and is primarily made up of a protein called flagellin.

2. **Identifying the Parts of the Flagellum**: The bacterial flagellum consists of three main parts:
- **Filament**: This is the long, helical structure that extends from the bacterial surface and is responsible for the propulsive movement.
- **Hook**: This is a universal joint that connects the filament to the basal body and allows for the rotation of the filament.
- **Basal Body**: This acts as the motor of the flagellum and is embedded in the bacterial cell membrane. It consists of several rings that help in the rotation of the flagellum.

3. **Analyzing the Options**: The question asks which part is NOT a component of the bacterial flagellum. The options typically include:
- Filament
- Hook
- Basal Body
- Microtubule

4. **Identifying the Incorrect Option**: From the description, we know that the filament, hook, and basal body are all parts of the bacterial flagellum. However, microtubules are not part of the bacterial flagellum structure. Microtubules are found in eukaryotic cells and are components of structures like cilia and flagella in eukaryotes, but they do not exist in bacterial flagella.

5. **Conclusion**: Therefore, the part that is NOT a component of the bacterial flagellum is **microtubule**.

**Final Answer**: Bacterial flagellum consists of all the following parts except **microtubule**.

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