THE BEECHMONT CREST GUIDE TO BIOLOGICAL TERMS
FLAGELLA
Flagella are long, whip-like structures (consisting of protein fibers) that protrude from the surface of a bacterial cell. There may be only one flagellum, or many. Bacteria use the flagella for locomotion.
Bacteria rotate their flagella by using special membranes. In this regard, bacterial cells are unique. (Eukaryotic cells generally do not contain rotating parts.)