OBB Practice Questions - Olimpíada Brasileira De Biologia Exam

Four reduced cytochrome c molecules transfer 4 electrons through CuA, heme a, and the binuclear heme a3-CuB center to reduce one O2 to 2 H2O, pumping 4 H+ into the intermembrane space Two reduced ubiquinol (QH2) molecules transfer 4 electrons through iron-sulfur Rieske centers directly to elemental oxygen, translocating 8 H+ across the outer mitochondrial membrane into the surrounding cytosol Reduced NADH directly donates 2 electrons to an internal FMN prosthetic group within Complex IV, which passes them to cytochrome c with the obligate uptake of 4 matrix protons per oxygen atom reduced to peroxide Four oxidized cytochrome c molecules abstract 4 hydride ions from molecular oxygen, translocating 2 H+ into the mitochondrial matrix to generate stable hydrogen peroxide intermediates within the intermembrane space