In Bacterial flagellum the longest portion is:

Options

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

Answer

To answer the question "In bacterial flagellum, the longest portion is:", we can break down the solution into the following steps:

### Step 1: Understand the Structure of Bacterial Flagellum
The bacterial flagellum consists of three main structural components: the basal body, the hook, and the filament. Each of these components has a distinct function and structure.

### Step 2: Identify Each Component
- **Basal Body**: This part acts as the motor of the flagellum and is embedded in the bacterial cell membrane.
- **Hook**: This is a curved structure that connects the basal body to the filament.
- **Filament**: This is the long, whip-like structure that extends from the hook and is responsible for the movement of the bacterium.

### Step 3: Compare the Lengths of Each Component
Among these three components:
- The **filament** is significantly longer than both the hook and the basal body.
- The **hook** is relatively short and connects the filament to the basal body.
- The **basal body** is also shorter and is primarily involved in anchoring and motor function.

### Step 4: Conclusion
Based on the comparison, the longest portion of the bacterial flagellum is the **filament**.

### Final Answer
The longest portion of the bacterial flagellum is the **filament**.

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