Several appendages appear on the surface of microbes. These appendages are divided into groups used for movement and attachment. The most frequently found structure for movement is the flagellum (plural = flagella). Flagella permit the microbe to swim freely in the water. This structure is composed of protein filaments; and is found in most spiral shaped bacteria, about half of bacilli shaped bacteria and protists, and a few cocci. The flagella may be located on the ends of the cell (polar) or randomly found on the sides (peritrichous). Using the flagella (and cilia in some protists), the microbes can move toward food and away from unfavorable environmental conditions. It is thought that the site of the "ball and socket articulation" of the flagellum and the microbe cell contains receptors that respond to chemicals in the environment. Microbes "run" (straight forward movement) or "tumble" (forward and reverse movement) at amazing speeds for such little creatures. Paramecium has about 10,000-14,000 cilia on the cell surface and moves about 1000 microns per second; Thiospirillum has been clocked at 5200 microns per minute; Pseudomonas moves at rates of 3400 microns per minute. These fast movers have polar flagella; however, E.coli with its peritrichous flagella moves about 1000 microns per minute. Considering their microscopic size, these microbes move quite rapidly.

The appendages not used for movement are called pili and fimbrae. The two terms are often interchanged; but we will consider the longer and less abundant appendages as pili. Pili are probably only found in gram-negative bacteria and are involved in exchange of DNA during a primitive type of sexual reproduction called conjugation. Yes, there is sex life among the microbes; and the pilus of the donor cell unites with a recipient cell, and genetic material between closely-related species may occur. The shorter and more numerous fimbrae are responsible for attaching microbe to food and even host cells. Fimbrae attach microbes to rocks and help microbes cling to each other on the surface of liquids. Streptococcus, E.coli, and Neisseria are examples of bacteria that have been observed to have fimbrae which help the organisms attach to cells lining the gastro-intestinal and uro-genital tracts.