Structure and function
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Prokaryotic Flagellum-
A bacterial flagellum has 3 basic parts: a filament, a hook, and a basal body.
1) The filament is the rigid, helical structure that extends from the cell surface.
2) The hook is a flexible coupling between the filament and the basal body
3) The basal body consists of a rod and a series of rings that anchor the flagellum to the cell wall and the cytoplasmic membrane
Eukaryotic Flagellum-
1. monotrichous: a single flagellum, usually at one pole
2. amphitrichous: a single flagellum at both ends of the organism
3. lophotrichous: two or more flagella at one or both poles
4. peritrichous: flagella over the entire surface
5. Axial filaments: internal flagella found only in the spirochetes. Axial filaments are composed of from two to over a hundred axial fibrils (or endoflagella) that extend from both ends of the bacterium between the outer membrane and the cell wall, often overlapping in the center of the cell.
A driving force occurs as protons accumulate between the membrane and the cell wall. Most bacterial flagella can rotate both counterclockwise and clockwise and this rotation contributes to the bacterium's ability to change direction as it swims. A protein switch in the molecular motor of the body controls the direction of rotation.
A bacterial flagellum has 3 basic parts: a filament, a hook, and a basal body.
1) The filament is the rigid, helical structure that extends from the cell surface.
2) The hook is a flexible coupling between the filament and the basal body
3) The basal body consists of a rod and a series of rings that anchor the flagellum to the cell wall and the cytoplasmic membrane
Eukaryotic Flagellum-
1. monotrichous: a single flagellum, usually at one pole
2. amphitrichous: a single flagellum at both ends of the organism
3. lophotrichous: two or more flagella at one or both poles
4. peritrichous: flagella over the entire surface
5. Axial filaments: internal flagella found only in the spirochetes. Axial filaments are composed of from two to over a hundred axial fibrils (or endoflagella) that extend from both ends of the bacterium between the outer membrane and the cell wall, often overlapping in the center of the cell.
A driving force occurs as protons accumulate between the membrane and the cell wall. Most bacterial flagella can rotate both counterclockwise and clockwise and this rotation contributes to the bacterium's ability to change direction as it swims. A protein switch in the molecular motor of the body controls the direction of rotation.