Question

Why does mitochondrial NADH yields more ATPs than cytosolic NADH?

Answer 1

Mitochondrial NADH yields more ATPs than cytosolic NADH as Electron transfer from cytosol to matrix can take more than one pathway.

The mitochondrion contains electrons from cytosolic NADH through one of two shuttle mechanisms: the malate–aspartate shuttle, which ultimately moves these electrons to mitochondrial NAD⁺ , and the glycerol 3-phosphate shuttle, which ultimately moves these electrons to mitochondrial FAD.

It is known that electrons can use more than one pathway—one of which loses energy that could be used for ATP synthesis—that accounts for the potentially decreased yield of ATP from cytosolic NADH.