Bacteria use appendages called flagella to move. Flagella are composed of protein subunits called flagellin. Flagella can be located at one or both ends of a bacteria (polar flagellation) or spaced over the entire surface of the cell (peritrichous flagellation).
The appendages are not straight, but helical shaped (like a wave). The flagella for each species of bacteria have a constant wavelength (the distance between each wave in the flagella).
Unlike the human hair, a flagellum grows from the tip, not the base. Flagellin protein is made in the cell and transported through a hollow center to the tip of the flagellum. Therefore, if a tip is broke off, a new one is regenerated. The flagella are stiff structures and move only at the base, like a propeller.
The average speed of a bacteria is 50 micrometers per second. If the bacteria were the size of a cheetah, it would move at about 30 miles an hour.


