BIOL 2004 Lecture Notes - Lecture 13: Ftsz, Staphylococcus, Thylakoid
Document Summary
External appendages: common in prokaryotes, usually made of protein, extracellular: usually anchored to cell membrane, or outer membrane, or both, bacterial flagella thin, flexible helical filaments (not straight, curl around an axis) : (5-20 microliters; ~15 nm thick) Present in many bacterial groups often only expressed under certain conditions. Monotrichous cell = one flagellum (not very common!) Peritrichous: many flagella all over surface: e. coli. Basal body: ring of motor proteins in cell membrane surrounding rotor. A rotary motor powered by proton motive force. Flagella can rotate clockise and counter-clockwise (ccw: usually goes ccw, different motility effects. In come peritrichous cells: all ccw: flagellar bundle forms; straight-line. Run": 1+ clockwise: no bundle, random tumble". Will not move in a semi-random fashion, usually in place can cause a cell to switch directions. Swimming: alternating runs and (random) tumbles random walk" through space.
