glycocalyx capsule Wikipedia:Capsule_(microbiology) A protective structure surrounding some fungi and bacteria, attached externally to the cell wall and composed primarily of polysaccharides. Capsules are highly organized structures that adhere strongly to cells and cannot be easily removed. Capsules play important roles in pathogenicity, preventing phagocytosis by other cells, adherence, and resistance to desiccation. GO:0030113 GO:0042603 cellular_component GO:0042604