BIOL 2004 Study Guide - Comprehensive Final Exam Guide - Prokaryote, Flagellum, Bacteria
20 Nov 2018
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Usually made from protein must be secreted to form extracellular structure. Usually anchored to cell membrane or outer membrane (or both) Motor proteins are attached to cell membrane in gram-negative. Examples: bacterial flagella, consists on thin, flexible helical filaments (5-20 um long; ~15 nm thick. Basal body = ring like structure of motor proteins in cell membrane surrounding rotor. A series of intrinsic proteins surround basal body. A rotary motor is powered by a proton motive force (pmf) *through the membrane down the proton gradient. Can rotate clockwise or counter-clockwise *different motility effects. In some peritrichous cells: if all are counter-clockwise flagellar bundle forms; straight-line run , if 1+ are clockwise no bundle; random tumble ; cell will spin in place. Swimming: alternating runs and random tumbles random walk through space, random walk can be biased by altering the frequency of random tumbles in response to a cue, e. g.
