Question

+8 A chemical prevents the reaction NADH →NAD. (be careful, this is not exactly the same as the practice question from the in class assignment) Assuming everything else stays the same in the cell and considering only the direct immediate effects of this drug, think about how this will affect cellular respiration. (3pts) A. In which stage(s) of cellular respiration does this reaction NADH → NAD normally occur? B. If the chemical is present, which stage(s) of cellular respiration will still occur? Which stage(s) of cellular respiration will not occur? (think only direct effects of drug) C. If the chemical is present, will the cell make less ATP or more ATP per glucose? Explain.

Answer 1

Ans: a) NADH acts as a reduced coenzyme containing high energy electrons which are utilized in the production of ATP during the oxidative phosphorylation which takes place after glycolysis and TCA cycle. In this stage the conversion of NADH into NAD⁺ normally occurs.

b) Since we know that the chemical basically catalyze the reaction of NADH into NAD⁺ so process of oxidative phosphorylation will still occur, but all the other stages like glycolysis, pyruvate oxidation and TCA cycle which require the step of the conversion of NAD⁺ into NADH so that it is able to act as donor of high energy electrons will not occur.

c) If the chemical is present the cell make less ATP per glucose because even it is catalyzing the oxidative phosphorylation step but it also halting all the previous reaction and because of this NADH is not able to contain high energy electrons so ATP production is less as compared to the normal cell.