Bacterial wall
It is a rigid shell that is mainly composed of peptidoglycans (murein). It is located between the plasma membrane and the bacterial capsule, if it exists. It is between 50 and 100 Å thick.
According to the Gram stain, two types of bacterial wall are distinguished.
- The Gram positive wall is monostratified and is made up of a thick basal layer of peptidoglycans (murein), to which proteins, polysaccharides and teichoic acids are associated.
- The Gram negative wall is bi-stratified, with a thin basal layer of peptidoglycans, on which there is a double lipid layer that contains a large number of proteins, most with enzymatic activity, and glycolipids. This layer is called the outer membrane.
The bacterial wall is responsible for maintaining the shape of the bacteria and protecting it against changes in the osmotic pressure of the medium.