The enzyme ATP synthase catalyzes the phosphorylation of ADP to form ATP. In eukaryotic cells, the energy needed for this endergonic reaction is derived from . View Available Hint(s) The enzyme ATP synthase catalyzes the phosphorylation of ADP to form ATP. In eukaryotic cells, the energy needed for this endergonic reaction is derived from . the fermentation of pyruvate to form lactic acid the reduction of NAD to form NADH the movement of FADH2 from the cytoplasm to the mitochondria the movement of hydrogen ions across the mitochondrial membrane