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

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