BIOL 2004 Lecture 13: Prokaryote Cell Components
10 Mar 2017
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Document Summary
Functions of cell membrane - from previous lecture. Selective permeability - controlled movement of most molecules into and out of cytoplasm. Forming proton (h+) gradient; harnessing of proton motive force (pmf: detection of environmental signals, protein anchor, (some) structural support, attachment of chromosomes, especially during cell division. External projections: usually made of protein, extracellular - usually anchored to cell membrane, or outer membrane, or both, examples, bacterial flagella, fimbriae and pili, nanowires (not tested) Bacterial flagella: thin, flexible helical filaments, 5-20micrometers long, about 15nm thick, not tested, present in many bacterial groups, often only expressed under certain conditions. Function - swimming locomotion: can rotate clockwise and counter-clockwise (ccw, the different directions gives different motility effects. If all are counter clock-wise (ccw), or clock-wise (cw): flagellar bundle forms a straight line, allows them to "run" Moving toward a chemical attractant: other patterns, peritrichous - many flagella all over surface.
