Chapter 4: Prokaryotic and Eukaryotic Cells

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Chapter 4: Prokaryotic and Eukaryotic Cells
2013-02-27 22:05:33
Micobio Exam

Functional Anatomy of Prokaryotic and Eukaryotic Cells
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  1. Prokaryotes: distinguishing characteristics
    • 1. Dna  has no enclosed membrane
    • 2. lack membrane enclosed organelles
    • 3. cell walls are complex polysacharide peptidoglycan
    • 4. Divide with binary fission
  2. Eukaryotes
    • 1.Has nucleus to sep dna from cytoplasm
    • 2. have many membrane enclosed organeles
    • 3. chemically simple cell walls.
    • 4. cell division: mitosis.
  3. Prokaryote vs Eukaryote Structures (image)
  4. Plasma Membranes: Prokaryote vs. Eukaryote
    BOTH have it!

    similarities: phospholipid bilayer with proteins, separates cells from outside

    Differences: not applicable
  5. Cell Wall: Prokaryote vs. Eukaryote
    • Prokaryote:
    • Bacteria has peptidoglycan;
    • Archea-Pseudopeptidoglycan

    • Eukayotes:
    • Fungi: Chitin
    • Plants&Algae: Cellulose

    Similarities: structural support, resists bursting, made of polysaccharides

    Differences: Chemical composition; some eukaryote do lack cell walls
  6. Chromosome (genetic material)
    Prokaryotes: Circular, only one chromosome in "nucleoid" region

    Eukaryotes: Linear, variable number of chromosomes/associated with histone protiens

    • Similarities: Made of DNA
    • Differences: Different (?) and organization
  7. Nucleus: Prokaryote vs. Eukaryote
    • Prokaryote: NONE
    • Eukaryote: Present :D

  8. Flagellum: Prokaryote vs. Eukaryote
    Prokaryote: Rotational motion in Bacteria

    Eukaryote: whiplike in animals

    • Similarities: Locomotion
    • Differences: Diff type of motion & chem compositon
  9. Ribosomes: Prokaryote vs. Eukaryote
    • Prokaryote: Present
    • Eukaryote: Present, some associated with RER

    • Similarities: Protein synthesis
    • Diffs: prok have smaller ribosomes
  10. Membrane Bound Organelles: Prokaryote vs. Eukaryote
    • Prokaryote: NOT PRESENT,
    • Eukaryote: Rough ER, Mitochondria, Golgi Body, lysosomes, chloroplast

    • Similarities:None.
    • Differences: Prok lack; euk often have several membrane bound organelles
  11. Capsule (pg 70)
    • Firmly attached to cell wall (made of glycolax-gelatinous polymer)
    • -protect pathogenic bacteria from phagocytosis :(
  12. Slime Layer
    • another type of glycolax;
    • Loose, thinner, flexible attached to cell
    • -Helps bacteria attach to surface
  13. Endospores (70. 95-97)
    -purpose and characteristics
    -endospore components
    Resting structures formed by some bacteria, allows for survival during adverse environmental conditions (dry conditions)

    • Characteristics:
    • very little water
    • resistant to heat, uv rays and disinfectants

    • Components: cytoplasm, plasma membrane, ribosomes, peptidoglycan, spore coat (protein) and dipicolinic acid
    • Locations: terminal(very end), central and subterminal (almost end)

    ex: clostridium tetani
  14. Sporulation:

    • 1. DNA is replicated
    • 2. Endospore forms when plasma membrane, peptidoglycan layer, and spore coat surround DNA
    • 3. endopsore is related as vegative cell disintegrates

     "germination": return of endospore to it's vegetative state
  15. Practice questions:
    1. How do you get rid of endospores?
    2. How is an endospore diff from a begetative cell?
    3. can bacteria reproduce by using endospores?
    4. what would happen if an endospore got into bloodstream of a patient?
    5. Do we need to strilize our food to get rid of endospores?
    • 1. calibrate by increasing or decreasing temp
    • 4. spermination
    • 5. Pasteurization, canned food: get rid of botchulism endospores
  16. EPS: extracellular polymeric substance
    a glycocalyx that helps cells in biofilm attach to target environment and allow bacteria to survive
  17. Endoplasmic Reticulum (ER) & RER
    • Nuclear envelop attached to Endoplasmic Reticulum (ER)
    • --surface for chem reactions and transport network.
    • --RER: protein synthesis/transport
  18. Golgi complex:
    flattened sacs (cisterns); fuctions in membrane formation & protein secretions
  19. Lysosomes:
    form by golgi complexes; store digestive enzymes
  20. vacuoles:
    memb enclosed cavities; give rigidity to plant cells
  21. Mitochondria
    • primary ATP site production;
    • contain 70S ribosomes & dna.-multiply by binary fission
  22. Peptidoglycan:
    polymer consisting of NAG (N-acetylglucosamine) & NAM (N-acetylmuramic acid) and short amino acid chains; penicillin interferes with this wall

    --in gram positive cell walls; crystal violet combines with peptidoglycan but decolorizer removed the lipid outer memb of gram negative bacteria and washes out crystal violet.

    Gram neg walls: thin peptidoglycan layer and a lipopolysaccharide-lipoprotien-phospholipid layer (-.-)
  23. Gram Negative cells (chemical structure)
    • -MUCH more complex-Thin layer of peptidoglycan
    • -LPS (lipopolysaccaride)
    • -Porins
    • -Periplasms with chemoreceptors: gel like fluid between outer membrane and the plasma membrane
    • -NO teichoic acids;

    • OUTER membrane: contains LPS, lipoprotiens and phospholipids
    • --gives wall strong neg charge
    • --provides barrier to antibiotics, digestive enzymes,and dyes
    • --Porins: channels allow nucleotides, amino acids
  24. Gram Positive Cells (chemical structure)
    • -Many layers of peptidoglycan
    • -Thick ridgid structure
    • -teichoic acids: alcohols (glycerol) and phosphate; gives wall antigenic specificity to allow group into "gram pos" cells
  25. How do Gram stains work?
    -Crystal violet purpose
    -Iodine purpose
    -Alcohol effect to both walls
    - ADD what dye after, what kind of dye is this?
    -Based on differences between cell wall structure (type of differential stain)

    Crystal violet (primary) stain both cells

    Iodine: forms large crystals with dye that are TOO large to escape through wall

    Alcohol: dehydrates peptidoglycan of gram positive cells and make it more impermeable to crytal violet-iodine.  BUT on gram negative: the alcohol dissolves the outer membrane of gram negative cells and even leaves small holes in the thin peptidoglycan layer SO THAT crystal-violet-iodiine leaves!

    This is why safranin must be added to stain gram negative cells (turn them red)--contrasting stain
  26. Tetra peptide Side Chain
    • Composed of NAG & NAM
    • -NAG: N-acetylglucosamine
    • -NAM: N-Acetylmuramic acid
  27. Bacterial shapes:
    coccus, spiral, star, pleiomorphic
    • Rod/bacillus: cylinders
    • coccus: sphere
    • spiral: spirillium (w/flagella) or spirochete (axial filaments-rotate)
    • star
    • pleiomorphic: many shapes (corynebacterium diphtheriae-cause diphtheria)
    • coccobacilillus
  28. Bacterial Cell ARRANGEMENTS:
    • the ways cell stick together:
    • 1. strepto: chains of cells
    • 2. tetrad: group of 4 cells
    • 3. stahylo: grape like clusters
    • 4. palisade: picket fence
    • 5. diplococcus: two circle oo
  29. Cytoplasmic bodies
    Nutrient storage
    metachromatic granules
    • a. nutrient storage:
    • --> ex: polysaccharides granules for store starch
    • --> lipid inclusions store lipids
    • -->sulfur bacteria store sulfur as energy source

    • b. metachromatic granules with phosphate (turn red): inorganic phosphate storage
    • --> used to diagnose Corynebacterium diphtheriae

    c. magnetosomes: contains iron compounds, use to orignet to magnetic fields
  30. Pili and Fimbriae
    Pili: straight, hairlike, gene transfering

    Fimbria: straight hairlike for attachment ex: neisseria gonorrheae
  31. Flagellum


    Parts of flagellum?
    long appendages that propel bacteria

    monotrichous: single flagellum at one pole

    Peritrichous: flagella distributed over entire cell

    amphitrichous: flagella at both poles of the cell

    flagellin: protein that is the main component of the filament

    • Main parts of flagella:
    • Basal Body-anchored the whole flagellum to the cell wall and PM
    • Hook: rotates
    • filaments
  32. Biofilms
    -Community of bacteria; form at liquid-solid interfaces; slime layer (extracellular polymeric substance-EPS:helps bacteria attach to surfaces)

    -protected from antibodies and antibiotics; wbc's create inflammation

    -found: teeth, rock in a pond, pet's waterdish

    • advantages of biofilm:
    • prevents dehydration
    • share nutrients
    • protection from host immune system (antibodies or wbc phagocytosis)
  33. Biofilms Review Questions:
    1. Explain how a biofillm protects bacteria from antibiotics
    2. Best way to get rid of biofilms
    • 1. Protective barrier
    • 2. Physically remove them
  34. Quorum Sensing:
    • Bacteria organize into communities using chemical communication to make biofilms,
    • disruption will allow for prevetnion