Select the incorrect statement.

Options

A. Bacterial cell wall is made up of peptidoglycan
B. Pili and fimbriae are mainly involved in motility of bacterial cells
C. Cyanobacteria lack flagellated cells
D. Mycoplasma is a wall-less microorganism

Answer

To solve the question of selecting the incorrect statement, we will analyze each statement provided in the question one by one.

### Step-by-Step Solution:

1. **Statement 1: Bacterial cell wall is made up of peptidoglycan.**
- This statement is **correct**. The cell wall of bacteria is primarily composed of peptidoglycan, which provides structural support and protection.

2. **Statement 2: Pilus and fimbriae are mainly involved in motility of bacterial cells.**
- This statement is **incorrect**. While pili and fimbriae play roles in attachment and conjugation, they are not primarily responsible for motility. The main structure responsible for bacterial motility is the flagellum.

3. **Statement 3: Cyanobacteria lack flagellated cells.**
- This statement is **partially correct**. While many cyanobacteria are non-motile and do not have flagella, some species can be motile. However, they are predominantly known for being non-flagellated.

4. **Statement 4: Mycoplasma is a wall-less microorganism.**
- This statement is **correct**. Mycoplasma are indeed unique among bacteria in that they lack a cell wall, making them the smallest known bacteria.

### Conclusion:
The statement that is incorrect is **Statement 2: Pilus and fimbriae are mainly involved in motility of bacterial cells.**

### Final Answer:
The incorrect statement is **Statement 2**.

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