Subject: There is a strain of E. coli that is unable to make its own amino acid alanine.
I am answering practice questions at the end of the chapter to get ready for a test.
This is a senario given that if I allow this bacterial strain to grow in medium containing alanine and then plate 10 to the 6th power cells on a petri dish containing medium with no alanine, I observe that an average of two colonies per plate will appear.
When you add blue dye #4 to the growth medium, twenty-two colonies appear. Can I conclude That my culture is contaminated with a phage? That blue dye #4 is a carcinogen? E. coli needs blue dye #4 for growth? Blue dye #4 is a mutagen? Blue dye #4 causes base substitutions? Alanine is a potential carcinogen?
That my culture is contaminated with a phage? No.
That blue dye #4 is a carcinogen? I don't believe that bacteria get cancer! Seriously though, just because blue dye #4 is a mutagen (see below) doesn't mean that it causes cancer.
E. coli needs blue ...