Micro Lab Quiz Question 6

Give 2 examples of a differential & selective growth media.

-differential: MacConkey agar, Starch agar -selective: Mannitol Salt Agar (MSA)

What is the protein in Milk agar that some organisms can hydrolyze via extracellular enzymes called?

Caseinase

EMB agar has the ability to directly ID a particular organism via the differential function. This organism will appear black with a metallic green sheen. What is this particular organism?

E. coli

Interpret the result for the organism streaked on the half left of the MacConkey agar. (picture)

Lactose fermentation occurred since that side of the plate changed to a pale color

Beta hemolysis is complete RBC lysis with formation of clear zone around bacteria. Name the 2 enzymes involved in bacteria hemolysis of the medium.

Streptolysin O and Streptolysin B

Organisms that are able to perform hydrolysis of the gelatin protein to amino acids is evident by liquefaction of the gelatin agar in the test tube after incubation and refrigeration. (true or false)

True

For citrate test citrase enzymes causes [ ] coloration on the surface of the slant green test tube if there is a positive reaction.

blue coloration

Describe definition of differential growth medium in a sentence.

causes change in color & clarity due to microbe biochemical activities like fermentation

The organism on the right is able to perform lipid hydrolysis as indicated on the Tributyrin agar seen below. What specific extracellular enzyme would this organism be positive for based on the results of the test? (picture)

lipase