Question

visualizing the concept: most atp production occurs by oxidative phosphorylation
what is being pumped through the inner mitochondrial membrane into the intermembrane space, as indicated by the green arrows?
electrons
fadh₂
nadh
hydrogen ions
atp

Explanation:

During oxidative phosphorylation in mitochondria, the electron - transport chain complexes pump hydrogen ions (protons) from the mitochondrial matrix into the intermembrane space, creating an electrochemical gradient. This gradient is then used by ATP synthase to produce ATP. Electrons are passed along the electron - transport chain but are not pumped across the membrane in the way indicated. FADH₂ and NADH donate electrons to the electron - transport chain but are not pumped across the inner mitochondrial membrane. ATP is synthesized in the matrix using the energy from the proton gradient, not pumped across the membrane in this context.

Answer:

hydrogen ions