In bacteria, a whiplike motility appendage present on the surface of some species. Flagella are composed of a protein called flagellin. Bacteria can have a single flagellum, a tuft at one pole, or multiple flagella covering the entire surface. In eukaryotes, flagella are threadlike protoplasmic extensions used to propel flagellates and sperm. Flage... Found on http://www.encyclo.co.uk/local/20973
long, rigid, spiral structures used by prokaryotic cells for motility in aqueous environments; composed of a filament made of flagellin, a hook, and motor (basal body) that are attached to the cell envelope Found on https://courses.lumenlearning.com/microbiology/chapter/glossary/