Peptidoglycan' is a characteristic constituent of the cell wall of

Options

A. Archaebacteria and Eucaryotes
B. Eubacteria and unicellular Eucaryotes
C. Bacteria and Cyanobacteria
D. Monera and Protista.

Answer

### Step-by-Step Solution:

1. **Understanding Peptidoglycan**: Peptidoglycan is a polymer that forms a mesh-like structure outside the plasma membrane of bacteria, providing structural support and shape to the cell wall.

2. **Identifying the Groups**: The question asks which group has peptidoglycan in its cell wall. We need to analyze the options given:
- **Archaebacteria and Eukaryotes**: Archaebacteria do not have peptidoglycan in their cell walls; they have different types of glycoproteins. Eukaryotes, such as plants and fungi, have cell walls made of cellulose and chitin, respectively.
- **Eubacteria and Unicellular Eukaryotes**: Eubacteria (true bacteria) have peptidoglycan in their cell walls, but unicellular eukaryotes (like protists) do not typically have peptidoglycan.
- **Bacteria and Cyanobacteria**: Both bacteria and cyanobacteria (blue-green algae) have peptidoglycan in their cell walls.
- **Monera and Protista**: Monera includes prokaryotes, which have peptidoglycan, but protista (which includes eukaryotes) do not have peptidoglycan.

3. **Conclusion**: The only correct option that includes organisms with peptidoglycan in their cell walls is **Bacteria and Cyanobacteria**.

### Final Answer:
Peptidoglycan is a characteristic constituent of the cell wall of **Bacteria and Cyanobacteria**.

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