Why is the yield of ATP from the complete oxidation of glucose lower in muscle and brain than in kidney, liver, and heart?
|A||Different shuttle mechanisms operate to transfer electrons from the cytosol to the mitochondria in the two sets of tissues|
|B||Muscle and brain cells have a lower requirement for ATP|
|C||There are fewer mitochondria in muscle and brain cells|
|D||There are fewer ATP syntheses in muscle and brain cells|
a. Muscle and brain use the glycerophosphate shuttle to transfer reducing equivalents through the mitochondrial membrane.
b. The glycerophosphate dehydrogenase inside the mitochondria utilizes FAD, whereas that in the cytosol uses NAD, resulting in only 2 mol of ATP produced instead of 3 ATP per atom of oxy gen.
c. In the malate shuttle used in the kidney, liver, and heart, the malate dehydrogenases on both sides of the mitochondrial membrane use NAD.