Which one does not have cellular structure ?

Options

A. Bacteriophage
B. PPLO
C. Bacterium attacking virus
D. Diatom

Answer

To answer the question "Which one does not have cellular structure?" we will analyze each option provided.

### Step-by-Step Solution:

1. **Identify the Options**: The options given are:
- A) Bacteriophage
- B) PPLO (Pleuro Pneumonia Like Organism)
- C) Bacterium attacking virus
- D) Diatom

2. **Analyze Each Option**:
- **Bacteriophage**: A bacteriophage is a type of virus that specifically infects bacteria. Viruses, including bacteriophages, do not have a cellular structure; they consist of genetic material (DNA or RNA) surrounded by a protein coat (capsid). Hence, they are considered non-living entities outside a host.

- **PPLO**: This stands for Pleuro Pneumonia Like Organism. PPLOs are a type of bacteria and therefore have a cellular structure. They are prokaryotic organisms.

- **Bacterium attacking virus**: This term seems to refer to a virus that infects bacteria, similar to a bacteriophage. Like bacteriophages, these viruses do not have a cellular structure.

- **Diatom**: Diatoms are a type of algae and are eukaryotic organisms. They have a cellular structure, including a cell wall made of silica.

3. **Conclusion**: Among the options, both bacteriophages and bacterium attacking viruses do not have a cellular structure. However, the term "bacterium attacking virus" is less commonly used and may refer to a bacteriophage. The most straightforward answer is **A) Bacteriophage**, as it is explicitly a virus.

### Final Answer:
The correct answer is **A) Bacteriophage**.

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