BCHM 3050 1st Editin Lecture 34 Outline of Last Lecture I. Amphibolic Nature of the TCA CycleII. Summary of Glycolysis and TCA CycleIII. Oxidation and ReductionIV. Reduction PotentialV. Overview of Electron Transport ChainOutline of Current Lecture I. Position of Four Complexes in Cristae MembraneII. Important Biomolecules Involved in Respiratory Electron TransportIII. Complex 1IV. Complex 2V. Complex 3VI. Complex 4VII. Reduction Potentials Along Electron Transport ChainVIII. “Poisons” are Inhibitors of Respiratory Electron TransportCurrent LectureI. Position of Four Complexes in Cristae Membranea. 1 molecule of glucose - in the cytoplasm glycolysis produces a net yield of 2 ATP and 2 NADH/H+b. In the mitochondria, the citric acid cycle is carried out in the matrix: 2 pyruvate à acetyle CoA (2 NADH/H+); 2 Acetyl CoA à 6 NADH/H+ and 2 FADH2c. Protons from NADH travel to the inter membrane space and used as energy (trigger ATP synthesis)d. These complexes are stationary – the complexes are full of proteins which accept protons from NADH and carry them onto other moleculese. Oxygen is the last electron acceptor à oxygen has the highest reduction potentialf. Complex 1 – oxidized NADH back to NAD+g. Complex 2 – succinate dehyrogenase generates FADH2, which gives up its electrons to other proteinsh. Complex 3- cytochromes gives up and takes electronsi. Complex 4- cytochrome c oxidase is conserved across species j. Oxygen gets protons at the end and is reduced to waterThese notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.k. This action happens in the inter-membrane spaceII. Important Biomolecules Involved in Respiratory Electron Transporta. Ubiquinone - fluid in nature and moves through the membranes to carry the electrons; more lipid than proteinb. Flavoproteins have bound FAD in them; accept and give up proteins – single or double electron/proton transfersc. Fe-S Proteins – non-hemoglobin proteins; single electron transfersd. Cytochromes – heme proteins; single electron transfere. CoQ = Ubiquinonef. There are 4 electron transfers that happen with complex 1g. Complex 1 is rich in flavoproteins and iron-sulfur proteins and ubiquinome; neverfind cytochromes or copper in Complex 1h. Complex 2 – succinate dehydrogenase complex; FADH2 passes electrons to Fe-S protein; end up giving protons to CoQ; receives electrons from FADH2i. Complex 3 – contains Fe-S proteins and cytochromes, no flavoproteinsj. Electrons go to cytochrome C outside of complex 3k. Complex 4 – has copper that accepts the electrons and donates them to oxygen to reduce it to waterl. Ubiquinone is the carrier that transfers electronsm. Cytochrome C transfers electrons from Complex 3 to 4III. Complex 1a. Complex 1 – contains flavoproteins, Fe-S proteins, and CoQb. Beta-oxidation is oxidation of fatty acids that generates NADHc. Accumulate 4 protons in the intermembrane spaced. When accepting electrons, also accepting protonse. For every NADH getting oxidized à sending 4 protons from the matrix into the intermembrane spaceIV. Complex 2a. Proton gradients are not established as a result of electron transport in/at/around complex II.b. Complex 2 – succinate dehydrogenase complexc. FaDH2 is converted to FAD, which is transferred to Ubiquinoned. NADH from glycolysis enters Complex 2e. Complex 2 does not generate any protons in the intermembrane spaceV. Complex 3a. Complex 3 – the Q cycle; has cytochromes and Fe-S protein (not flavoproteins); the electrons come solely from ubiquinone (not from NADH or FadH2 directly)b. In the end, cytochrome C will get all of the electronsc. 4 protons from Complex 3 from every NADH moleculed. Ubiquinone is the only molecule that transfers electrons to complex 3e. Cytochrome C is only present in the intermembrane spaceVI. Complex 4a. Complex 4 is rich in copper and donates electrons to oxygen to get reduced to waterb. Accumulate 2 protons from 1 NADH c. Accumulated 10 protons in the intermembrane space after all 4 complexesd. Cytochrome oxidase is the enzyme present here (evolutionary conserved)VII. Reduction Potentials Along Electron Transport Chaina. NADH has the lowest reduction potentialb. NADH is lowest, CoQ is higher, then Cyt C, and oxygen is the highest VIII. “Poisons” are Inhibitors of Respiratory Electron Transporta. Antimycin is an anti-fungal à blocks electron transfers within complex 3b. Carbon monoxide blocks the transfer of electrons from copper to oxygenc. Cyanide à blocks electron transfer from copper to oxygen alsod. Barbituate (truth serum) inhibits transfer of electrons from Complex 1 to Complex
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