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19 Cards in this Set
- Front
- Back
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Purpose of culture media |
to grow, transport, and store microorganisms in the lab |
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Synthetic/Defined Media |
All components and concentrations are known |
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Complex Media |
Contain some ingredients of known composition and/or concentration |
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Peptones |
protein hydrolysates prepared by partial digestion of various protein sources |
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Extracts |
aqueous extracts, usually beef or yeast |
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Agar |
sulfated polysaccharide used to solidify liquid media; most microorganisms cannot degrade it |
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Supportive/ General purpose media |
supports the growth of many microorganisms (TSA) |
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Enriched media |
-favors the growth of some microorganisms without inhibiting the growth of others General purpose media supplemented by blood or other special nutrients (blood agar) |
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Selective Media |
favor the growth of some microorganisms and inhibit the growth of others (MacConkey agar - selective for gram-negative bacteria) |
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Differential Media |
distinguish between different groups of microorganisms based on their biological characteristics |
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Differential characteristic of blood agar |
hemolytic vs non-hemolytic bacteria |
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MacConkey agar |
lactose fermenters vs non-fermenters |
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Strict Anaerobic Microbes |
-lack superoxide dismutase and catalase -cannot tolerate O2 -must be grown without oxygen |
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Isolation of pure cultures |
-population of cells arising from a single cell -developed by Robert Koch -spread plate, streak plate, pour plate |
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Streak Plate |
-involves technique of spreading a mixture of cells on an agar surface so that individual cells are well separated from each other -each cells can reproduce to form a separate colony |
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Spread Plate |
-Small volume of diluted mixture containing approximately 30-300 cells is transferred -spread evenly over surface with a sterile bent rod |
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Pour Plate |
-sample is serially diluted -diluted samples are mixed with liquid agar -mixture of cells and agar are poured into sterile plate |
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More organisms grow at the _____ rather than the _____ of an agar surface because _______. |
edge, center, more oxygen and nutrients, less toxic products and dead cells |
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Biofilm |
group of surface-associated microbial cells that is enclosed in an extracellular polymeric substance matrix |
