Microbiology 020 - General Microbiology » Fall 2021 » Lab Quiz 4 Selective and Differential Media

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Question #1
After inoculation, if MSA turns ______, the presumptive ID is ______.
A.   Yellow; Staphylococcus aureus
B.   Yellow; Coliform
C.   Red; Staphyloccus aureus
D.   Red; Non-coliform
E.   Red; Coliform
Question #2
What is the differential agent in MSA?
A.   Mannitol
B.   Lactose
C.   7.5% NaCl
D.   Phenol red
E.   Peptone
Question #3
Pink growth on MacConkey agar indicates the bacterium ______.
A.   Does not ferment sucrose only
B.   Ferments lactose
C.   Does not ferment lactose or sucrose
D.   Ferments sucrose only
E.   Is gram +
F.   Does not ferment lactose only
Question #4
The selective agent(s) in EMB is ________.
A.   Lactose
B.   Phenol red
C.   Eosin & Methylene Blue
D.   Peptne
E.   Agar
Question #5
If a clearing is present on an inoculated starch hydrolysis plate, the bacterium makes the enzyme _____.
A.   Superoxide dismutase
B.   Cytochrome C oxidase
C.   Gelatinase
D.   Catalase
E.   Amylase
Question #6
The catalase is most often used to differentiate ________ species.
A.   Coliform
B.   Enterobacteriaceae
C.   Micrococcaceae & Streptococcaceae
D.   Enterococcus
Question #7
Incomplete hemolysis on blood agar is indicated by observing _____.
A.   Clearing around growth
B.   Production of a black precipitate
C.   Greening around growth
D.   No change in the medium
Question #8
On blood agar, streptolysin O expresses maximal activity under _____ conditions.
A.   Aerobic
B.   Facultative
C.   Microaerophilic
D.   Anaerobic

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