Bio 2010 - Microbiology » Spring 2023 » Lab Quiz 5

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Question #1
A __________ is a clear zone on a lawn of bacteria that represents where viruses have replicated and killed cells.
A.   spot
B.   plaque
C.   mutation
D.   zone of inhibition
Question #2
Why do we wait 15 minutes after adding a virus to an E. coli sample before mixing it with warm agar and pouring on an agar plate?
A.   To prevent the plates from being too watery.
B.   To prevent excessive contamination when pouring warm agar on the plate.
C.   To allow the 0.5% agar to solidify.
D.   To allow the coliphage to come in contact with and infect E. coli cells.
Question #3
1 ml of a virus culture was added to 9 ml of sterile TSB. What is the final dilution of virus to broth in this tube?
A.   1/10,000
B.   1:100
C.   1:10
D.   1/1000
Question #4
The acronym PFU stands for
A.   polyformyl uracil
B.   colony-forming unit.
C.   pre-formed units
D.   plaque-forming unit.
Question #5
Which of the following media is MOST appropriate to use when performing a catalase test? (Think carefully)
A.   blood agar
B.   trypticase soy broth
C.   trypticase soy agar
D.   Columbia CNA
Question #6
Which of the following is a catalase-negative coccus?
A.   E. durans
B.   M. luteus
C.   S. epidermidis
D.   N. sicca
Question #7
α hemolysis causes an olive green color that represents.
A.   the partial breakdown of blood cells on BAP.
B.   the complete breakdown of blood cells on BAP.
C.   citrate utilization on Simmons citrate agar.
D.   no breakdown of red blood cells on BAP.
Question #8
This compound converts fibrinogen into fibrin in blood plasma.
A.   fibrolysin
B.   hemolysin
C.   coagulase
D.   cellulose
Question #9
Which of the following is α hemolytic, sensitive to optochin, resistant to bacitracin and will not grow on bile esculin agar?
A.   E. durans
B.   S. aureus
C.   S. pyogenes
D.   S. pneumoniae

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