What is the function of a capsule in bacteria?

The function of a capsule in bacteria primarily involves protection and adherence. A capsule is a thick, gelatinous layer composed of polysaccharides (and sometimes proteins) that surrounds the bacterial cell wall. One of its key roles is to protect bacteria from phagocytosis, which is the process by which immune cells engulf and destroy pathogens. By providing a physical barrier, the capsule helps bacteria evade the immune response.

Additionally, the capsule aids in adherence to surfaces, which is crucial for colonization and infection. This adherence is important for forming biofilms, which are communities of microorganisms that adhere to surfaces and are encased in a protective matrix. Overall, the presence of a capsule enhances bacterial virulence, making it a vital factor in pathogenicity.