Generation of proton gradients across membranes occurs during which of the following reactions?

Recognize the process involved: The electron transport chain is the key process that generates proton gradients by moving electrons through a series of complexes, which pump protons from the mitochondrial matrix to the intermembrane space.

Differentiate between the processes: The Calvin cycle occurs in chloroplasts and is involved in photosynthesis, not in generating proton gradients. Glycolysis occurs in the cytoplasm and does not involve membrane-bound proton gradients. The Krebs cycle occurs in the mitochondrial matrix but does not directly generate proton gradients.