91Ó°ÊÓ

Question: Describe the structure and function of the six primary electron carriers in the mitochondrial electron transport system. Answer: In the mitochondrial electron transport system, the six primary electron carriers include: 1. NADH and FADH2, which act as primary electron donors and are derived from B-vitamins. 2. Coenzyme Q (CoQ or ubiquinone), a lipid-soluble molecule that functions as a mobile electron carrier by transferring electrons from Complex I and II to Complex III. 3. Cytochromes (b, c, c1, a, a3), which are heme-containing proteins responsible for electron transfer, and in particular, cytochrome c transfers electrons between Complex III and Complex IV. 4. Iron-sulfur proteins, such as ferredoxin, which contain iron and sulfur atoms bound to a protein and facilitate electron transfer within various ETC complexes. 5. Copper ions (Cu), found in Complex IV and organized in redox-active metal centers called CuA and CuB, which help transfer electrons from cytochrome c to molecular oxygen to produce water. Each of these electron carriers play a unique role in driving ATP synthesis through oxidative phosphorylation in the electron transport chain.