This set up has 3 questions.  Each is worth 1 point. Samples…

This set up has 3 questions.  Each is worth 1 point. Samples of the same pure culture were incubated in tubes 2-5.  These tubes demonstrate the reactions of this organism over a period of 48 hours. A.  What does the yellow color in tubes 2 and 3 indicate about the metabolism of the organism? [A] B.  What change has occurred in the medium between tube 3 and tube 5? (What does the color change indicate about the medium?) [B] C.  In metabolic terms, what caused the color change seen in tube 5? (What metabolic pathway did the organism use to cause the change in the medium?) [C]