Prince George Community College » Biology » Bio 2010 - Microbiology » Summer 2022

Question #1

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 allow the coliphage to come in contact with and infect E. coli cells.

B. To prevent excessive contamination when pouring warm agar on the plate.

C. To prevent the plates from being too watery.

D. To allow the 0.5% agar to solidify.

Question #2

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. 1/1000

D. 1:10

Question #3

The acronym PFU stands for

A. pre-formed units

B. plaque-forming unit.

C. colony-forming unit.

D. polyformyl uracil

Question #4

Which of the following is a catalase-negative coccus?

A. S. epidermidis

B. E. durans

C. N. sicca

D. M. luteus

Question #5

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. no breakdown of red blood cells on BAP.

D. citrate utilization on Simmons citrate agar.

Question #6

This compound converts fibrinogen into fibrin in blood plasma.

A. hemolysin

B. cellulose

C. coagulase

D. fibrolysin

Question #7

Which of the following is α hemolytic, sensitive to optochin, resistant to bacitracin and will not grow on bile esculin agar?

A. S. pneumoniae

B. S. aureus

C. S. pyogenes

D. E. durans