Select incorrect statement for bacterial flagella : Option 1 The filament is a hollow rigid cylindrical structure made of the protein called tubulin. Option 2 The filament measures about 20 nm in diameter and 1 −70 nm in length. Option 3 The basal body is the most complex part of the flagellum and consists of four rings connected to a central rod in Gram-negative bacteria. Option 4 Filament rotate by 360 ∘ rather thane undulating back and forth like a whip.

Options

A. The filament is a hollow rigid cylindrical structure made of the protein called tubulin.
B. The filament measures about `20` nm in diameter and `1-70` nm in length.
C. The basal body is the most complex part of the flagellum and consists of four rings connected to a central rod in Gram-negative bacteria.
D. Filament rotate by `360^(@)` rather thane undulating back and forth like a whip.

Answer

To determine the incorrect statement regarding bacterial flagella, we will analyze each option step by step.

### Step-by-Step Solution:

1. **Understanding Bacterial Flagella**:
Bacterial flagella are long, thin, filamentous structures that enable bacteria to move. They are rigid and have a specific structure comprising three main parts: the basal body, hook, and filament.

2. **Analyzing Option 1**:
- **Statement**: "The filament is a hollow rigid cylindrical structure made of the protein called tubulin."
- **Evaluation**: This statement is incorrect because bacterial flagella are made of a protein called **flagellin**, not tubulin. Tubulin is the protein found in eukaryotic flagella.

3. **Analyzing Option 2**:
- **Statement**: "The filament measures about 20 nm in diameter and 1 − 70 nm in length."
- **Evaluation**: This statement is correct. The diameter of bacterial flagella is approximately 20 nm, and their length can range from 1 to 70 nm.

4. **Analyzing Option 3**:
- **Statement**: "The basal body is the most complex part of the flagellum and consists of four rings connected to a central rod in Gram-negative bacteria."
- **Evaluation**: This statement is correct. The basal body of Gram-negative bacteria does consist of four rings (L, P, M, S) connected to a central rod.

5. **Analyzing Option 4**:
- **Statement**: "Filament rotates by 360° rather than undulating back and forth like a whip."
- **Evaluation**: This statement is also correct. Bacterial flagella rotate in a circular motion, allowing for efficient movement.

### Conclusion:
The incorrect statement regarding bacterial flagella is **Option 1**: "The filament is a hollow rigid cylindrical structure made of the protein called tubulin."

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