Definition for Flagella
From Biology Forums Dictionary
The structures responsible for cell motility include flagella: long extensions from the cell surface and glycocalyx that propel a cell through its environment. Bacterial flagella are composed of a filament, a hook, and a basal body. Flagella covering the cell are termed peritrichous flagella, and those found at the ends of a cell are called polar flagella.
Flagella enable bacterial cells to move clockwise or counterclockwise, in a series of runs and tumbles. Via taxis, flagella move the cell toward or away from stimuli such as chemicals (chemotaxis) or light (phototaxis).
See Also: Endoflagella