The cell wall is absent in Mycoplasma.
Mycoplasmas are a genus of bacteria known for their unique characteristic: the lack of a cell wall. This distinguishes them from most other bacteria, which possess a rigid cell wall that provides shape, protection, and structural support.
Why is the absence of a cell wall significant?
The absence of a cell wall in Mycoplasma has several important implications:
- Pleomorphism: Without a cell wall, Mycoplasma cells are pleomorphic, meaning they can vary in shape. They don't have a fixed shape like many other bacteria.
- Resistance to certain antibiotics: Many antibiotics, such as penicillin and other beta-lactam antibiotics, work by targeting the synthesis of the bacterial cell wall. Since Mycoplasmas lack a cell wall, they are naturally resistant to these types of antibiotics.
- Dependence on sterols: To compensate for the lack of a cell wall and maintain membrane stability, Mycoplasma often incorporate sterols (like cholesterol) into their cell membranes, which they obtain from their environment or host.
Examples of Mycoplasma Species
Several Mycoplasma species are pathogenic, causing diseases in humans, animals, and plants. Examples include:
- Mycoplasma pneumoniae: Causes atypical pneumonia (walking pneumonia) in humans.
- Mycoplasma genitalium: A sexually transmitted infection associated with urethritis, cervicitis, and pelvic inflammatory disease.
Summary
In summary, Mycoplasma is a genus of bacteria notable for the absence of a cell wall, leading to pleomorphism, resistance to certain antibiotics, and a dependence on sterols for membrane stability.
