Which one is peritrichous?

Options

A. vibrio
B. Bacillus typhosus
C. Spirillium
D. Nitrosomonas

Answer

To determine which organism has a peritrichous arrangement of flagella, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Flagella Arrangements**:
- There are four main types of flagella arrangements in bacteria:
- **Monotrichous**: A single flagellum at one end.
- **Amphitrichous**: One or more flagella at both ends.
- **Lophotrichous**: A tuft or cluster of flagella at one or both ends.
- **Peritrichous**: Flagella distributed all over the surface of the bacterial cell.

2. **Analyze the Options**:
- We have the following options: Vibrio, Bacillus typhosus, Spirulum, and Nitrosomonas.

3. **Identify Each Organism's Flagella Arrangement**:
- **Vibrio**: Has a monotrichous arrangement (one flagellum at one end).
- **Bacillus typhosus**: Exhibits a peritrichous arrangement (flagella all over the surface).
- **Spirulum**: Shows a lophotrichous arrangement (a tuft of flagella at one end).
- **Nitrosomonas**: Usually does not have flagella or shows limited movement.

4. **Select the Correct Answer**:
- Based on the analysis, **Bacillus typhosus** is the only organism that has a peritrichous arrangement of flagella.

### Final Answer:
- The organism that is peritrichous is **Bacillus typhosus**.

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