MICRO exam 2

Term
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____ media contain substances that inhibit the growth of unwanted organism while showing your microbe of interest to grow.
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Terms in this set (19)
____ media contain substances that inhibit the growth of unwanted organism while showing your microbe of interest to grow.
Selective
Culture media can be prepared in both solid and liquid form. Liquid media is referred to as ____ while solid media is made by adding ____ to liquid media.
broth, agar
What would you expect to see on a gram stain for both a Gram-positive and a Gram-negative bacterium if you
a.) Forget to treat with iodine for one minute?
The crystal violet dye would wash right out if iodine is not used after
What would you expect to see on a gram stain for both a Gram-positive and a Gram-negative bacterium if you
b.) Have too many cells of your bacterium?
Bacteria would be too dense to distinguish them apart
What instrument is used to sterilize media at 121'C and 15 psi for 15-20 minutes?
autoclave
What is obtained through use of streak plate method
a pure culture
How are heat-liable compounds sterilized when added to culture media?
Filtration
Results in complete lysis of red blood cells
beta hemolysis
Seen as a green-brown discoloration
alpha hemolysis
Growth with no hemolysis
gamma hemolysis
How does 95% ethanol affect cells of Gram-positive and Gram-negative bacteria, respectively, during a gram stain?Gram-positive helps lock in dye, Gram-negative washes out crystal violet-iodineA medium contains 30 g K2HPO4, 20 g dextrose, and 5 g NaCl. Is this a complex or defined medium?defined medium____ media permit a visual distinction between various microorganisms.differentialWhat does LPS stand for?LipopolysacharrideWhat complex macromolecule helps from the cell wall of most bacteria?peptidoglycanName one Gram-positive and one Gram-negative microbe.Gram-negative, E.coli; Gram-postive, M.LuteusInhibits the growth of Gram-positive bacteria while using lactose to identity strong acid producers with a metallic green sheen.Eosin-methylene blue agarInhibits Gram-negative growth while using phenol red to identify acid producers with a yellow color change.Mannitol salt agarInhibits the growth of Gram-positive bacteria while using neutral red to identify colonies fermenting lactose.MacConkey agar