Aerobic Respiration - Exercise #6

Your lab uses the facultative anaerobe E. coli K-12 strain MG1655 as its model organism.  You have been asked to study some of the enzymes involved in aerobic respiration.

  1. You are specifically looking at NADH dehydrogenase I and II (NDH-1 and NDH-2).  Upon examining their reactions, you notice something uniquely different between the two.  What is it?  (Hint: look at their enzymatic reaction diagram)


  3. Only NDH-1 functions under microaerophilic conditions; expression of the NDH-2 gene is repressed when molecular oxygen levels are low.  Explain why.