Bacterial capsule (may be missing)
It is a viscous outer layer with a thickness ranging between 100 and 400 Å. It is very common in pathogenic bacteria because it facilitates adherence to the host's tissues. It is not present in all prokaryotes .
This capsule is rich in polysaccharides and protein molecules.
The bacterial capsule is attributed the following functions:
- Attach the pathogenic bacteria to its host.
- It protects the bacteria from the drying medium.
- It regulates the processes of exchange of water and nutrients, in addition to serving as a storehouse of nutrients.
- Defense against antibodies, bacteriophages and phagocytic cells.
- It allows the formation of colonies of bacteria.