Bmsc 210 Mid1 p3

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  1. Morphology
    cell shape
  2. Coccus (pl. cocci):
    spherical or ovoid
  3. Rod:
    cylindrical shape
  4. Spirillum:
    spiral shape
  5. Cells with unusual shapes
    – Spirochetes, appendaged bacteria, and filamentous bacteria
  6. Size range for prokaryotes: ____ μm to > ___ μm indiameter
  7. Most cultured rod-shaped bacteria are between ____ and____μm wide and <__ μm long
    • 0.5-4.0um wide
    • <15 um long
  8. Two examples of large prokaryotes
    • • Epulopiscium fishelsoni
    • • Thiomargarita namibiensis
  9. Size range for eukaryotic cells: ___ to >___ μm indiameter
    10 to >200 μm
  10. Advantages to being a small cell
    • Small cells have more surface area relative to cell volume than large cells (i.e., higher S/V)
    • – support greater nutrient exchange per unit cellvolume
    • – tend to grow faster than larger cells
  11. Cytoplasmic membrane
    • – Thin structure that surrounds the cell
    • – 6–8 nm thick
    • – Vital barrier that separates cytoplasm from environment
    • – Highly selective permeable barrier; enablesconcentration of specific metabolites andexcretion of waste products
  12. Sterols
    • Rigid, planar lipids found in eukaryotic membranes Strengthen and stabilize membranes
  13. What two ions help stabilize membrane by forming ionic bonds with negative charges on the phospholipids
    Mg2+ and Ca2+
  14. Hopanoids
    • • Structurally similar to sterols
    • • Present in membranes of many Bacteria
    • very hydrophobic planar structure
  15. Arcahaeal Membranes
    -what kind of linkages in phosholipids?
    • – Ether linkages in phospholipids of Archaea(H-H)
  16. Bacteria and Eukarya that have ___ linkages in phospholipids
    • ester (B.E.ST)
  17. Archaeal lipids lack fatty acids, have____instead
    • isoprenes
  18. in Archaeal Membranes the Major lipids are ____ _____ and _______
    • glycerol diethers and tetraethers
  19. Do Archael membranes exist as monolayers, bilayers or a mixture?
    they can exist as lipid monolayers, bilayers, or mixture
  20. Group translocation:
    • A mechanism utilized by bacteria to transport a compound into their cell by first allowing the compound to bind with protein on the cell surface followed by altering its chemical structure during its passage across the membrane. driven by phosphoenolpyruvate
    • -The Phosphotransferase System in E. coli
  21. Uniporters
    • -transport in one direction across the membrane
    • -ex:K+ in, power by electrical difference between out and in
  22. – Symporters
    • function as co-transporters
    • -Lactose is transported into E. coli by the simple transporter lac permease, a symporter (lactose and H+)
    • -Activity of lac permease is driven by proton gradient
  23. Antiporters
    • -transport a molecule across themembrane while simultaneously transporting another molecule in the opposite direction
    • -ex:Na+ out H+ in
  24. The Phosphotransferase System in E. coli
    • – Type of group translocation: substance transported is chemically modified during transport across the membrane
    • – Best-studied system
    • – Moves glucose, fructose, and mannose– Five proteins required
    • – Energy derived from phosphoenolpyruvate
    • -Phosphate group is attached to molecule being transported
    • Hpr- heat stable protein
    • Enz1 provides energy from Phosphoenolpyruvate in form of phosphate
    • Phosphate is transfered from component to component untill enz2c where it drives transport of and is bonded to the sugar
  25. periplasmic binding proteins
    Binds to substrate in periplasm and then binds to mouth of a transporter to pass substrate through to cytoplasm
  26. • ABC (ATP-Binding Cassette) Systems
    • – >200 different systems identified inprokaryotes
    • – Often involved in uptake of organiccompounds (e.g., sugars, amino acids),inorganic nutrients (e.g., sulfate, phosphate),and trace metals
    • – Typically display high substrate specificity
    • – Contain periplasmic binding proteins
  27. NAG
    • N-acetylglucosamine
    • Glucose attached to acetyl group (C2)
  28. NAM
    • N-acetylmuramic acid
    • same as NAG apart from a chain branching from C3
    • 1-lactic acid
    • (4 aminos-Glycan tetrapeptide)
    • 2-L-alanine
    • 3-D-glutamic acid
    • 4-diaminopimelic acid(G+) or L-Lysine(G-)
    • 5-D-alanine
  29. Peptidoglycan
    • – Rigid layer that provides strength to cell wall
    • – Polysaccharide composed of
    • • N-acetylglucosamine (NAG) and N-acetylmuramic acid(NAM)
    • • Amino acids
    • • Lysine or diaminopimelic acid (DAP)
    • • Cross-linked differently in gram-negative bacteria and gram-positive bacteria (Figure 3.17)
    • - prominent in gram positive
    • -lysozyme sensitive bond
  30. Teichoic acid
    • bacterial polysaccharides of ribitol phosphate found on Gram positive bacteria
  31. • Gram-Positive Cell Walls
    • – Can contain up to 90% peptidoglycan
    • – Common to have teichoic acids(acidicsubstances) embedded in the cell wall
    • • Lipoteichoic acids: teichoic acids covalentlybound to membrane lipids
    • -NAM branch contains L-Lysene and extra 5 Glycene
  32. Gram negative Bacteria
    • • Total cell wall contains ~10% peptidoglycan(Figure 3.20a)
    • • Most of cell wall composed of outer membrane (outer layer of outer membrane composed of lipopolysaccharides [LPS] )
    • – LPS consists of core polysaccharide and O-polysaccharide
    • – LPS replaces most of phospholipids in outerhalf of outer membrane
    • – Endotoxin: the toxic component of LPS(what our body reacts to)
  33. Lipopolysaccharide (endo toxin)
    • -composed of Lipid A- 6 or 7 fatty acids attached to 2 glucosamine (toxic)
    • -Core polysaccharide- 7 specific sugars
    • -O-specific polysaccharide- antigen(sets off imune system) group of sugars repeated over and over
  34. Porins:
    channels for movement of hydrophilic low molecular weight substances in outer membrane
  35. Periplasm:
    – ~___ nm wide
    – Contents have ____-like consistency
    – Houses many ______
    • space located between cytoplasmic and outer membranes
    • – ~15 nm wide
    • – Contents have gel-like consistency
    • – Houses many proteins
  36. Energy conservation
    • how bacteria create energy through a proton gradient (high concentration of + out; low in(- on inside) polar membrane)
    • -proton flow into the cell (proton motive force) is harnessed for energy

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Bmsc 210 Mid1 p3
2013-02-02 05:12:06
Bmsc 210 Mid1 p3

Bmsc 210 Mid1 p3
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