Looking at Your Results of the Ames Test Using Bacteriological

Looking at your results of the Ames test using bacteriological agar medium plates lacking the amino acid histidine, you ?nd that there are many colonies growing on the agar. How do you interpret this result?

A) The bacterium has turned its operon genes on, producing proteins necessary for growth.
B) The chemical being tested is mutagenic.
C) The bacterium does not have any plasmids, so it cannot grow on the medium.
D) The drug being tested has no inhibitory effect on the bacterium; therefore, it is not a good antibiotic to give for treatment of disease.