Lab Quiz 2 Flashcards
6, 7, 8, 9
Pure culture definition
population of cells descending from a single cell, free of contamination
Aseptic definition
Free of contamination
Two goals of aseptic technique:
1) Prevent the introduction of unwanted microbes/contaminants in your sample
2) Avoid the sample from contaminating you or others
Testing aseptic technique in lab read lab if unsure
Control tube of E.coli, two practice tubes- results should show turbid for E.coli but clear for practice tubes = no contamination
Incubation definition:
Storing samples in an ideal environment (right temperature, right growth medium) for microorganisms to grow/replicate. We often store at 37 C
Chemically defined medium. Example and definition:
Ex: Glucose salts/mineral agar (GSA or GMA).
Def: A growth medium that has known amounts of elements (nutrients/chemicals - does not contain or is limited in growth factors
Complex medium. Example + definition
ex: TSA (tryptic soy agar), Nutrient broth
Def: A growth medium with a blend of chemicals (such as digested proteins) in unknown quantities. Does contain growth factors.
fastidious organism
requires many growth factors
enriched mediums
contains growth factors to support the growth of specific organism
selective medium
contains ingredients that inhibit the growth of particular bacteria
differential medium
gives visual indicators for bacteria. fermentation=lactic acid=purple
how to determine the dilution
=sample/(diluent + sample)
*concentration determination:
colonies on countable plate x (sample volume) x dilution
aerotolerant anaerobe
tolerates O2 but does not use it (fermenter)
O2 preference:
M.Lutens (soil)
M. Smegmatis
E. coli (intestine)
C. sporogenes (intestine)
M. Lutens: obligate aerobe
M. Smegmatis: obligate aerobe
E. coli: facultative anaerobe
C. sporogenes: obligate anaaerobe
