9-23-09 Notes

9 – 23 – 09
6. Motility: flagella and pili
a. pili: twitching motility: jerky motion of bacteria w/ pili along surface; pili attach to surface retract
b. Flagella (note: bacterial flagella are not the same as eukaryotic flagella(which are just elongated cilla)) – swimming smoothly through liquid. Flagella analogous to motor on submarine
i. Flagellar arrangements
1. Polar (ex. P. aeruginosa) – the bacteria have flagella located on one end or the other end maybe on both but not covering them everywhere.
Bacteria w/tuft of polar flagella or bacteria with dual flagella
2. Peritrichous (ex. E. coli) – having flagella all over.
Bacteria flagella are rigid (behave like propellers on a boat or plane behavior when moving about), flagellin filament attached to “motor” made of various integral membrane proteins
Eukaryotic Cilla(flagella): flexible: move like snakes
ii. Flagellin: protein that makes a flagelium filament,
Eukaryotic flagella and cilla: made of tublin and dynein.: interactions between these 2 proteins  snake-like motion of eukaryotic flagella
iii. Basal body and hook: basal body is whole set of proteins that are the “motor”, hook: connects basal body to flagellum filament
iv. Use of ATP – breaks down into ADP which fuel the transport of flagellum molecules are exported out through the hook where the polymerase together to for the flagellum filament spin flagellum by proton pump system
How they made:
- ATP broken down in to ADP +phosphate. This provides energy to export of flagellin proteins thru hook where they for the flagellum
How they move:
- A proton pump system: h+ are pumped across the plasma membrane of bacteria. The protons are trapped between the cell wall and plasma membrane because H+ are charged(and membrane has hydrophobic parts) protons can fall across a gate in flagellar basal body – this spins the basal body, which in turn spins the flagellum(sort of like a water wheel)
Next time look up the terms proton pump, find an example of another proton pump in which our cells are more familiar. Proton pump, mitochondria, endosymbiosis.

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