BIO205 CH6 PT2

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BIO205 CH6 PT2
2013-02-23 02:32:36
BIO205 CH6 PT2

BIO205 CH6 PT2
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  1. describe selective media
    3 examples of ingredients that select for certain types of bacteria
    • contain substances that either favor the growth of particular microbes or inhibit the growth of unwanted ones
    • dyes, bile salts may be added to inhibit growth of G+ bacteria, letting G- bacteria grow
  2. Describe differential media.
    3 examples of visible indicators in differential media.
    • Presence of visible changes in the media
    • Blood, pH indicators, Gas production
  3. how does blood agar distinguish between alpha, beta, and gamma hemolysis?
    • alpha: greenish color
    • beta: clear zone around colonies
    • gamma: agar unchanged 
  4. Describe MacConkey agar-
    and ingredients that allow it to be both selective and differential media.
    3 microorganisms
    • Crystal violet: lactose, Bile salts, Neutral red
    • differential media- distinguish diff. in color and selective enhance growth
  5. Be able to interpret sugar fermentation tube results
    • red= no fermentation
    • yellow= acid fermentation
    • bubble= gas production
  6. what kind of media is used for obligate anaerobes; what substance is added that removes O2?
    • Reducing media
    • Sodium thioglycollate
  7. What is transport media used?
    • so people are not infected
    • so samples are not contaminated
  8. Give examples of microorganisms that must be grown in live animals, eggs or cells cultures.
    • Leprosy and syphillis grown in animals= armadillos & rabbits
    • Viruses, rickettsia, chlamydia in cells
  9. what are candle jars used for?
    • Low oxygen culture= organisms that require low levels of oxygen 
    • _ areotolerant anaerobes, microaerophiles, capnophiles
  10. Explain how enrichment culture can be used to increase a microbe population
    use selective media
  11. Describe 3 ways of preserving cultures
    • Refrigeration: short-term preservation
    • prevents accumulation of waste
    • Deep freezing: 50c to 95c
    • can be stored for years
    • Lyophilization: Freeze drying
    • last for decades