Select the incorrect statement.

Options

A. Nostoc and Anabaena have heterocysts for nitrogens fixation.
B. Cyanobacteria often form blooms in polluted water bodies
C. Heterotrophic bacteria are more abundant in nature
D. The cell wall of Mycoplasma are made up of chitin

Answer

To solve the question of identifying the incorrect statement, we will analyze each of the four statements provided:

1. **Statement 1**: "Nostoc and Anabaena have heterocyst for nitrogen fixation."
- **Analysis**: This statement is true. Nostoc and Anabaena are types of cyanobacteria that possess specialized cells called heterocysts, which are involved in nitrogen fixation.

2. **Statement 2**: "Cyanobacteria often form blooms in polluted water bodies."
- **Analysis**: This statement is also true. Cyanobacteria can proliferate rapidly in nutrient-rich (polluted) waters, leading to blooms that can have harmful effects on aquatic ecosystems.

3. **Statement 3**: "Heterotrophic bacteria are more abundant in nature."
- **Analysis**: This statement is true as well. Heterotrophic bacteria, which obtain their nutrients by consuming organic matter, are indeed more abundant in various environments compared to other types of bacteria.

4. **Statement 4**: "The cell wall of mycoplasma is made up of chitin."
- **Analysis**: This statement is incorrect. Mycoplasma are unique among bacteria because they lack a cell wall entirely. They are also resistant to antibiotics that target cell wall synthesis, and their membranes are composed of lipids and proteins, not chitin.

**Conclusion**: The incorrect statement is the fourth one: "The cell wall of mycoplasma is made up of chitin."