Flagella (singular: flagellum) are long, thin, whip-like appendages attached to a bacterial cell that allow for bacterial movement. Bacterial cells are typically between 0.1 micrometers and 50 micrometers in diameter, but average around 2 micrometers.
What is the flagellum in sperm for?
Sperm swim by means of a prominent flagellum, composed of a core of microtubules, whose sliding is powered by flagellar dynein. This array of microtubules and associated motor and linker proteins is known as an axoneme.
How does the flagellum work?
Bacterial flagella are helically shaped structures containing the protein flagellin. The base of the flagellum (the hook) near the cell surface is attached to the basal body enclosed in the cell envelope. The flagellum rotates in a clockwise or counterclockwise direction, in a motion similar to that of a propeller.