Biochemistry - Bacterial Flagella

Biochemistry - Bacterial Flagella 
Many bacterial cells feature one or more flagella, which are tail-like extensions. Chemotaxis is the term for the ability of bacteria to move across the extracellular medium by rotating their flagella in the direction of attractants and away from repellents. Both bacterial flagella and eukaryotic cilia and flagella are made of the protein flagellin (53 kDa subunit), which is different from tubulin.

Additionally, bacterial flagella rotate as opposed to bend. About six flagella protrude from various locations on the cell surface of an E. coli bacteria. Flagella are little, 10 mm long, helical filaments with a diameter of 15 nm. According to electron microscopy, the flagellar filament consists of 11 subunits arranged in two helical turns, giving it the appearance of an 11-bladed propeller with a hollow centre when viewed end-on. New flagellin subunits are added to the end of the flagellum that faces away from the cell, and these new subunits diffuse across the central core of the flagellum. The flagellar motor is located at its base in the plasma membrane and is a complex assembly of about 40 proteins. A passage of protons through certain proteins in the flagellar motor causes the flagella to rotate. The F0F1-adenosine triphosphatase (ATPase), which produces adenosine triphosphate (ATP), also has a proton-driven motor.