2. Bacteria

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Author:
cornpops
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92366
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2. Bacteria
Updated:
2011-07-07 04:10:13
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PH162A midterm1
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public health microbiology lecture 2
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  1. Big 3
    AIDS, Tuberculosis, Malaria
  2. 3 domains of life
    • bacteria
    • eucaria
    • archea
  3. prokaryotic cell vs. eukaryotic cell
    • smaller
    • lacks nucleus an other membrane bound organelles
  4. size
    0.2-2um
  5. Shapes
    • bacillus - rod
    • coccus - spherical
    • spirllum - spiral
    • spirochaeta - corkscrew
    • vibrio - comma
  6. pleomorphic
    species with multiple shapes
  7. colony
    large mass of bacteria descene from a single bacterium
  8. metabolism
    entire set of chemical reactions whih maintain life in a cell
  9. Types of metabolism
    • phototrophs - energy from sunlight
    • lithotrophs - energy from inorganic compounds
    • organo(chemo)trophs - energy from organic compounds

    • carbon from CO2: -autotroph
    • carbon from organic compounds: -heterotroph

    chemoheterotroph: most pathogens
  10. aerobic
    need oxygen for growth
  11. microaerophilic
    need reduced oxygen level for growth
  12. anaerobic
    need absence of oxygen for growth
  13. facultative
    able to grow with or without oxygen
  14. locomotion
    • postive and negative chemotaxis
    • movement
    • attachment
  15. composition of flagella
    filament is a triple helix of proteins
  16. axial filaments
    • found in sprial shaped bacteria
    • internal to cell wall, wrap around body
    • undulating contractions of proteins causes movement
  17. Pili (or fimbria)
    • short filament extending from surface
    • function in attachment, not locomotion
  18. capsule
    • thick polysaccharide coat exterior to cell wall
    • important in protecting pathogens from engulfment and digestion by white blood cells
  19. endospore
    • metabolically dormant, non-reproductive
    • protects against changes in temperature and moisture
    • differentiates inside of the cell
    • allows survival in extremely adverse environmental conditions
  20. cell wall
    • protects against rupture due to changes in osmotic pressure
    • consists of peptidoglycan:
    • - unique carbohydrate
    • - alternating units of NAM and NAG
    • - peptide crosslinks
  21. gram + vs. gram -
    Gram +: thick layer of peptidoglycan with teichoic acid and lipteichoic acid, no outer membrane

    Gram -: thin layer of peptidoglycan, outer membrane with protein, lipopolysaccharide
  22. gram stain
    gram negative loses crystal violet and becomes pink
  23. acid-fast bacteria
    • thin layer of peptidoglycan, outer lipid layer
    • - high mycolic acid content causes cell to resist decolorization by acid
    • use alternate ziehl-neelsen stain
  24. reproduction
    • have single chromosome - circular
    • some have plasmids
    • reproduce through binary fission
    • genetic diversity made by transformation, conjucation and transduction
  25. transformation
    uptake of free DNA from environment
  26. conjugation
    • begins with sex pilus, special structure to make bridge between cells (often plasmid encoded)
    • DNA is replicated as it is transferred
    • donor retains plasmid, recipient receives copy
  27. transduction
    transfer of DNA from one cell to another by way of a bacteriophage
  28. beneficial aspects
    • metabolisms (recycling of elements in nature, bioegradation, bioremediation, endosymbionts)
    • industrial uses (antibiotics, food processing, biotechnology)
    • disease prevention - microflora helps prevent colonization of pathogens
    • model organisms
  29. detrimental aspects
    • food spoilage
    • human disease

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