There are usually 100s of pili per cell. These fine hair-like, protein structures on the cell wall are pili. In most cases they have special binding proteins at the end of the stiff rods. These types of pili are often important in adhesion of the cell to surfaces, such as teeth. Bacteria that move about using flagella always have the flagella arranged in a way that is descriptive of each bacteria.
Flagella are long , rigid protein rods that provide movement to many motile bacteria.
These layers are usually composed of sugar polymers that are excreted by the cell under certain conditions. The capsule has several roles. Magnets inside magnetotaxic bacteria. Bacteria demonstrate several types of taxis. Furthermore different bacteria see different colored lights .