MBIO 1

  1. Flagella and pili are what?
    External structures extending from the cell membrane through the cell wall and beyond it.
  2. Flagella (pl), Flagellum (sin)
    • External structure as way of movement w/speed and apparent purpose.
    • Long, thin, helical appendages.
    • Composed of flagellin - Protein subunits.
    • Basal region.
  3. Monotrichous
    • Bacteria w/ a single flagellum located at one end /pole.
    • Polar
  4. Amphitrichous
    • Bacteria w/ 2 flagella, one at ea. end/pole.
    • Polar
  5. Lophotrichous
    Bacteria w/ 2 or more flagella at one or both ends.
  6. Peritrichous
    Bacteria w/ flagella all over the surface.
  7. Atrichous
    • Bacteria w/o flagella.
    • Cocci rarely have flagella.
  8. Flagella: Gm (+)
    • 2 rings =
    • 1 outer protein ring to cell wall/thick peptidoglycan.
    • 1 inner protein ring to cell membrane.
  9. Basal Region
    • Attachement site for flagellum.
    • Consists of protein other than flagellin.
    • Contains hooklike structure and basal body.
    • Basal Body - central rod/shaft surrounded by a set of rings.
  10. Flagella: Gm (-)
    • 3 main parts = filament, hook, basal body.
    • Basal body: 2 outer rings + rod + 2 inner rings
    • 4 rings =
    • 2 Outer rings: Cell wall = outer membrane + peptidoglycan
    • 2 Inner rings: Cell membrane; lipopolysaccharide
  11. Chemotaxis
    Bacteria move toward or away from substances in their environment by a nonrandom process.
  12. (+) Chemotaxis
    • Moving --> attractant - lengthen runs, reduces freq of tumbles.
    • Moving <-- attractant - shortens run, inc freq of tumbles.
  13. (-) Chemotaxis
    • lower [harmful subs] <-- repellant - longer runs, few tumbles
    • higher [harmful subs] <--repellant - short urns, many tumbles
  14. Endoflagella
    • External motility structure composed of axial filaments; lie between outer sheath and cell wall; anchored at one end of a cell.
    • Spirochete - corkscrew rotation movement
  15. Pili (pl) , Pilus (sin)
    • Tiny hollow projection that allow attachements to surfaces. Not involved in movement.
    • 2 kinds...
  16. Conjuagtion Pili
    • AKA - F pili / sex pili.
    • Donor cell forms hollow bridge between similar bacterial cells for DNA transfer.
    • One of the sources of antibiotic-resistant baceria.
  17. Fimbriae
    • AKA - Attachment pili
    • Contribute to the pathogenicity (ability to produce disease) by enhancing colonization.
    • N. gonorrhoeae - attaches to epithelial cells of urogenital system.
    • Pellicle - Aerobic bacteria forming a shiny/fuzzy thin layer at the air-water interface of a broth culture.
  18. Glycocalyx
    • All polysaccharide containing substances found external to pro. cell wall. Usually sticky.
    • Capsules - most organized and thickest, prevents phagocytosis, increases pathenogenicity.
    • Slime Layer - unorganized, thin, loose. All bacteria have at least a thin slime layer.
Author
Anonymous
ID
110509
Card Set
MBIO 1
Description
Prokaryotic structures
Updated