Question

4. A bacterium is discovered with new mutated form of isocitrate dehydrogenase that catalyzes the same reaction but produces hydrogen gas instead of NADH. a. Write a balanced equation for the new reaction. b. What affect does this mutation have on the amount of ATP produced from one glucose molecule

Answer 1

Isocitrate + NAD+ -> a-ketoglutarate + CO2 + H2

The amount of ATP produced from one molecule of glucose will decrease because NADH is no longer produced in the isocitrate dehydrogenase reaction. Without generation of this high energy electron carrier there will be less electrons from one molecule of glucose that are transferred to and through the electron transport chain. So there will be less protons (H+ ions) pumped into the intermembrane space. So there will be less of a H+ ion gradient across the inner mitochondrial membrane to drive the synthesis of ATP by ATP synthase.