Biochemistry Exam 2 Review.docx. On electron transport.2021.

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Electron Transport Chain Where does ET and Oxidative Phosphorylation occur? - Mitochondrial inner Membrane What are the electron carriers in ET? Are they one or two electrons? - Flavoproteins (con... tain FAD or FMN), 1 or 2 - Iron-Sulfur Proteins, 1, 2, 3 - CoQ, 1 or 2 - Cytochromes, 2, 3, or 4 Which electron transfers are the most energetically stable? - FMNCoQ - Cyt bCyt c - Cyta  O2 What do the protein complexes in the ETC do? 1. Complex 1(NADH-CoQ Reductase): o contains FMN and iron/sulfur clusters o Takes 2 electrons from NADH and uses FeS to carry them one at a time o Acts as a proton pump: NADH + Q + 5H+(matrix) NAD + QH2 + 4H+(intermembrane) 2. Complex 2 (Succinate-CoQ Reductase) o Transfers electrons from succinate through FAD and some FeS clusters to CoQ o Does NOT pump protons to the intermembrane 3. Complex 3 o Transfers electrons from CoQH2 to cytochrome c in the intermembrane o Only accepts 1 electron at a time (but two binding sites, so 2 total) o 4 total H+ transferred to intermembrane 4. Complex 4 o Catalyzes transfer of electrons from cytochrome c to O2 o Pumps 2 H+ intermembrane per 2 electrons What order are they in? Complex 1+2 complex 3complex 4cyt cO2 Where does FADH2 and NADH enter the pathway? - NADH: Complex 1 - FADH2: Complex 2 What steps pump protons across the membrane? [Show More]

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