Question

1. The pH for the water in the MSA recipe is expected to be from 7.2-7.6. If the pH was too low, what could you expect to see? Select one:

a. The entire plate would be yellow

b. Nothing abnormal

c. The agar would crack at pH 6.5

d. E. coli would turn purple

2. Which of the following would the MSA medium NOT be considered: Select one:

a. Complex medium

b. Chemically defined medium

c. Differential medium

d. Selective medium

3. If you took a swab from a patient and cultured it on a MSA plate, which of the following could be identified by just using this test? Select one:

a. Staphylococcus epidermidis

b. Escherichia coli

c. Staphylococcus aureus

d. Micrococcus luteus

4. If you streaked the 3 organisms in this lab on a PEA plate and after incubating for 2 days at 37 degrees Celcius nothing grew (but they did grow on a NA plate made at the same time and grown in the same conditions), which of the following is the most likely cause for this result? Select one:

a. The agar was toxic.

b. The beef extract was bad.

c. The temperature was too low.

d. Too much phenylethyl alcohol was used

. e. The temperature was too high.

5. Why is the NA plate inoculated in addition to the Columbia CNA with 5% sheep blood agar plate? Select one:

a. Used to compare growth on non-selective medium

b. Used as second selective medium

c. Used to promote hemolysis

d. Used because it is easier to see

e. Used as a practice plate