Final answer:
The redox potential along the mitochondrial Electron Transport Chain decreases as electrons move from carriers with higher reduction potentials to those with lower potentials, releasing energy that is harnessed for ATP synthesis.
Step-by-step explanation:
Along the mitochondrial Electron Transport Chain (ETC), the redox potential (electron affinity) changes as electrons flow from carriers with higher reduction potentials to those with lower reduction potentials. This transfer process occurs through complexes I, III, and IV located in the inner mitochondrial membrane. Complexes and enzymes function as H+ pumps, using the energy released to establish an electrochemical gradient across the membrane. The resultant proton gradient powers the synthesis of ATP from ADP and inorganic phosphate (Pi) by ATP synthase during oxidative phosphorylation.
The electron affinity decreases along the ETC as the energy of the electrons is progressively used to pump protons, creating an electrochemical potential. This gradient is then harnessed to produce ATP, the cell's energy currency. In each successive redox reaction, there is also a drop in free energy, which gets stored temporarily in the generated gradient, evidencing a carefully orchestrated energy transformation system essential for cellular respiration.