Murein is not found in the cell wall of

Options

A. Diatoms
B. Nostoc
C. Eubacteria
D. Blue green algae.

Answer

To answer the question "Murein is not found in the cell wall of," we need to analyze the options provided and understand the composition of the cell walls of the organisms mentioned.

### Step-by-Step Solution:

1. **Understanding Murein**:
- Murein, also known as peptidoglycan, is a polymer that consists of sugars and amino acids. It is a key component of the cell walls of many prokaryotes, particularly bacteria.

2. **Identifying the Options**:
- The options given are:
- A) Diatoms
- B) Nostoc
- C) Eubacteria
- D) Blue-green algae

3. **Analyzing Each Option**:
- **A) Diatoms**:
- Diatoms are unicellular algae classified under the kingdom Protista. Their cell walls are primarily composed of silica (SiO2), not murein. Therefore, diatoms do not contain murein.
- **B) Nostoc**:
- Nostoc is a genus of cyanobacteria (also known as blue-green algae). Cyanobacteria have cell walls that contain murein. Thus, Nostoc does contain murein.
- **C) Eubacteria**:
- Eubacteria are a large group of bacteria that also have murein in their cell walls. Therefore, Eubacteria contain murein.
- **D) Blue-green algae**:
- Blue-green algae is another term for cyanobacteria, which also possess murein in their cell walls. Thus, blue-green algae contain murein.

4. **Conclusion**:
- The only organism from the options that does not have murein in its cell wall is **A) Diatoms**.

### Final Answer:
Murein is not found in the cell wall of **Diatoms**.

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