Block One Lecture 8

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Block One Lecture 8
2014-09-20 20:24:31
Test One
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  1. Comparing Prokaryotic and Eukaryotic Cells:

    Prokaryote comes from the Greek words for __. Eukaryote comes from the Greek words for __.
    • prenucleus
    • true nucleus.
  2. Contrast pro and euk: 

    - chromosome
    - DNA associated proteins
    - organelles
    - cell wall
    - reproduction
    • - one circular chromosome, not in a membrane
    • - paired chromosomes, in nuclear membrane

    • - no histones
    • - histones

    • - no organelles
    • - organelles

    • -peptidoglycan cell walls
    • - polysaccharide cell walls

    • - binary fission
    • - mitotic spindle
  3. Average size of prokaryotes

    0.2-1.0 um x 2-8 um

    circular, rod shaped, commas, spirals
  4. Unusual shapes

    What are most bacteria? A few are __
    • star shaped Stella
    • square Haloarcula

    most bacteria are monomorphi

    a few are pleomorphic
  5. Arrangements of bacteria
    pairs: diplococci, diplobacilli

    clusters: staphylococci

    chains: streptococci, streptobacilli
  6. Glycocalyx
    • - outside cell wall
    • - usually sticky
    • - a capsule is neatly organized
    • - a slime layer is unorganized adn loose
    • - extracellular polysaccharide allows cell to attach
    • - capsules prevent phagocytosis
  7. Explain flagella
    • outside cell wall
    • made of chains of flagellin
    • attached to a protein hook
    • anchored to the wall and membrane by the basal body
  8. Motile cells
    rotate flagella to run or tumble

    move toward or away form stimuli (taxis)

    flagella proteins are H antigens
  9. What are H antigens?
    the antigen in the flagella of motile bacteria; important in serologic classification of enteric bacteria
  10. axial filaments

    in spirochetes

    anchored at one end of a cell

    rotation causes cell to move
  11. Fimbriae allow __. 

    Pili are used to __.

    used to transfer DNA from one cell to another
  12. Cell wall

    - prevents __
    - made of __
    • osmotic lysis
    • peptidoglycan (in bacteria)
  13. Explain peptidoglycan
    polymer of disaccharde N-acetylglucosamine (NAG) and N-acetylmuramic acid (NAM)

    linked by polypeptides
  14. Compare gram positive cell walls and gram negative
    • +: thick peptidoglycan
    • -: thin peptidoglycan

    • +: teichoic acids
    • -: no teichoic acid

    • +: in acid-fast cells, contains mycolic acid
    • -: outer membrane
  15. Explain teichoic acids

    What do they do?
    • lipoteichoic acid links to plasma membrane
    • wall teichoic acid links to peptidoglycan

    • may regulate movement of cations
    • polysaccharides provide antigenic variation
  16. Gram negative outer membrane
    lipopolysaccharides, lipoproteins, phospholipids

    forms the periplasm between the outer membrane and the plasma membrane

    protection from phagocytes, complement, antibiotics

    O polysaccharide antigen

    Lipid A is an endotoxin

    Porins (proteins) form channels through membrane
  17. What are O polysaccharide antigens?
    presence or absence of O chains determines whether the LPS is considered rough or smooth.
  18. Gram Stain Mechanism
    • CV-I crystals form in cell
    • Gram-positive
    • --- alcohol dehydrates peptidoglycan
    • --- CV-I crystals do not leave

    • Gram negative: 
    • --- alcohol dissolves outer membrane and leaves holes in peptidoglycan
    • --- CVI washes out
  19. Atypical Cell Walls
    mycoplasmas: lack cell walls/ sterols in plasma membrane

    Archaea: wall-less, or walls of pseudomurein (lack NAM and D amino acids)
  20. Damage to Cell Walls
    Lysozyme digests disaccharide in peptidoglycan.

    Penicillin inhibits peptide bridges in peptidoglycan.

    Protoplast is a wall-less cell.Spheroplast is a wall-less Gram-positive cell.

    L forms are wall-less cells that swell into irregular shapes.

    Protoplasts and spheroplasts are susceptible to osmotic lysis.
  21. Plasma membrane: composition
    • phospholipid bilayer
    • peripheral proteins
    • integral proteins
    • transmembrane proteins
  22. Fluid Mosaic Model
    membrane is as viscous as olive oil

    proteins move to function

    phospholipids rotate and move laterally
  23. plasma membrane: What it allows?
    selective permeability allows passage of some molecules

    enzymes for ATP production

    photosynthetic pigments on foldings called chromatophores or thylakoids
  24. Damage to the membrane by __, __, and __ cause __ of cell contents.
    alcohols, quaternary ammonim (deterents), polymixin antibiotics

  25. Movement across membranes
    simple diffusion: movement of a solute from an area of high concentration to an area of low n

    facilitative diffusion: solute combines with a transporter protein in the membrane
  26. Movement across membranes continued
    osmosis: movement of water across a selectively permeable membrane from an area of high water concentration to an area of lower water

    osmotic pressure: the pressure needed to stop the mvement of water across the membrane
  27. Isotonic solution:
    no net movement of water; same solutes throughout
  28. Hypotonic (hypoosmotic) solution
    water moves into the cell, which is more highly concentrated, causing the cell to burst if the wall is weak or damaged (lysis)
  29. Hypertonic (hyperosmotic) solution
    water moves out of the cell (which is more highly concentrated), causing its cytoplasm to shrink
  30. Cytoplasm
    inside the plasma membrane
  31. Nuclear area
    nuclear area (nucleoid)
  32. What are some inclusions (14)
    • Metachromatic granules (volutin
    • Polysaccharide granules
    • Lipid inclusions
    • Sulfur granules
    • Carboxysomes 
    • Gas vacuoles 
    • Magnetosomes  
    • Phosphate reserves
    • Energy reserves
    • Energy reserves
    • Energy reserves
    • Ribulose 1,5-diphosphate carboxylase for CO2 fixation
    • Protein covered cylinders
    • Iron oxide
    • (destroys H2O2)
  33. Endospores
    • Resting cells
    • Resistant to desiccation, heat, chemicals
    • Bacillus, Clostridium
    • Sporulation: Endospore formation
    • Germination: Return to vegetative state
  34. Eukaryotic cells

    - motility?
    - have both flagella and cilia

    -- microtubules (tubulin) (9 pairs + 2 arrangements)
  35. Cell wall of eukaryotes
    cell wall: plants, algae, fungi, carbohydrates

    Cellulose, chitin, glucan, mannan

    Glycocalyx: carbohydrates extending from animal plasma membrane; bonded to proteins and lipids in membrane
  36. Phospholipid bilayer of eukaryotes
    phospholipid bilayer

    peripheral proteins

    integral proteins

    transmembrane proteins


    glycocalyx carbohydrates
  37. Movement through the eukaryotic plasma membrane
    selective permeability allows passage of some molecules

    • simple and facilitative diffusion
    • osmosis

    active transport

    • endocytosis: phagocytosis--pseudopods extend and engulf particles
    • --pinocytosis: membrane folds inward bringing in fluid and dissolved substances
  38. Eukaryotic cell structures

    - cytoplasm

    • - Substance inside plasma and outside nucleus
    • - fluid portion of cytoplasm
  39. Eukaryotic cell structures

    -cytoplasmic streaming
    - microfilaments, intermediate filaments, microtubules

    - movement of cytoplasm throughout cells
  40. Membrane bound organelles:

    - nucleus

    - ER

    - GOlgi

    - Lysosome
    nucleus: contains chromosomes

    ER: transporot network

    Golgi: membrane formation and secretion

    Lysosome: Digestive enzymes
  41. Membrane bound organelles:

    - vacuole

    - mitochondrion

    - chloroplast

    - peroxisome
    • - brings food into cells and provides support
    • - cellular respiration
    • - photosynthesis
    • - oxidation of fatty acids; destroys H2O2
  42. Eukaryotic cell: not membrane bound

    - ribosome
    - centrosome
    - centriole
    • ribosome: protein synthesis
    • centrosome: consists of protein fibers and centrioles
    • centriole: mitotic spindle formation
  43. Ribosomes
    - Size
    80S: membrane bound ( attached to ER) and free (in cytoplasm)

    70S: in chloroplasts adn mitochondria