BCHM 3050 Lecture 36 Outline of Last Lecture I. “Alternate Oxidase” in PlantsII. Aerobic Respiration: ATP SynthesisIII. ATP Synthesis TerminologyIV. Three Sites in Electron Transport with Sufficient Energy Yield for ATP SynthesisV. Stoichiometry of Respiratory Electron TransportOutline of Current Lecture I. Stoichiometry of Respiratory Electron TransportII. Proton GradientsIII. Chemiosmotic TheoryIV. ATP SynthaseV. Binding Change Mechanism for ATP SynthesisVI. Glycerol-3-phosphate ShuttleVII. Aspartate-Malate ShuttleVIII. Reduced Nucleotides Are Not EnoughCurrent LectureI. Stoichiometry of Respiratory Electron Transporta. About 104 protons in the intermembrane space for 1 molecule of glucoseb. Totals: 8 NADH à 80 protons; 2 FADH2 à 12 protons; 2 NADH from cytoplasm after glycolysis ( go through complex 2, 3, and 4, not complex 1) à (2 x 6 protons) = 12 protonsc. 1 glucose = 104 protonsd. NADH goes through complex 1, 2, 3, 4 à 10 protons per 1 NADHe. FADH2 goes through complex 2, 3, 4 à 6 protons per 1 FADH2f. Matrix has low proton concentrationg. Intermembrane space has high proton concentrationh. Matrix – where pyruvate processing and TCA occuri. Innermembrane – Complex I-IV (ETC)j. Intermembrane space – increase proton accumulationThese 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. Very low pH and very high concentration of positive chargesà overload of positive charges is a proton motive sourceII. Proton Gradientsa. Imbalance of chemical charges will cause the charges to be pushed back to the matrix to even out the charges causing ATP to be synthesized (Chemi-Osmotic Coupling Theory)b. The movement of protons back into the matrix is known as the “proton motive force”III. Chemiosmotic Theorya. The part of the enzyme sticking out of the matrix is what synthesizes ATPb. Low pH and highly acidic space due to the high proton accumulation is located in the intermembrane spacec. Note: secretion/leakage of protons is due to the fact that the outermembrane is a bit more permeable to protons than the inner membrane.d. You can up tin certain molecules to disrupt the flow of protons back into the matrixe. Big difference in the voltage in the matrix versus the intermembrane spaceIV. ATP Synthasea. NADH à complex 1 makes 4 protons, complex 2 makes 4 protons, complex 4 makes 2 protons à total of 10 protonsb. FADH2 enters complex 2 and makes 6 protonsc. Pyruvate Processing and TCA à 8 NADH make 80 protons, 2 FADH2 make 12 protonsd. 2 NADH in cytoplasm enters complex 2 and makes 12 protonse. Total of 104 protons in the bodyf. F0 is embedded while F1 is free-floatingg. A and C work together to get the protons into the matrixh. When proton gets into the C complex, it will initiate movement of the rest of the complexi. Beta – active sites, where reactions happen, synthesis of ATPj. 3 subunits of beta so can get 3 ATPs at the same timek. Gamma – expose beta to ADP and inorganic phosphatel. Alpha – regulatory sitem. Binding of protons happens through the interface of A and C and is released fromC into the matrixV. Binding Change Mechanism for ATP Synthesisa. 3 types of betas à loose, open, and tightb. When 1 proton enters the matrix, ADP and inorganic phosphate bind and beta changes conformation from open into the loose form à 2nd proton into the matrix changes beta to the tight conformation and beta synthesizes ATP à 3rd proton the tight becomes open and releases an ATPc. Takes 3 protons to make 1 ATP from a beta (3 protons yields 1 ATP)d. Look over this picture, but do not need to memorize it because there are some flawsVI. Glycerol-3-phosphate Shuttlea. Do not confuse glycerol-3-phosphate with glyceraldehyde-3-phosphate (which is in glycolysis)b. Glycerol-3-phosphate - Helps NADH generated during glycolysis enter the membrane; tiny molecule that can easily pass through the mitochondria membrane; will give its electrons to FAD in the process à FADH2 which moves into Complex 2c. G3P is a reduced form of DHAPVII. Aspartate-Malate Shuttlea. In TCA, OAA gets converted to malate, but in this shuttle malate gets converted to OAAb. This shuttle produces and transports NADH, which goes to complex 1c. This only happens in the liverd. # protons that can accumulate in the live per one molecule of glucose = 112 H+ à 32 ATPe. Brain à 104 H+ = 30 ATPf. Overall, 30-32 ATP VIII. Reduced Nucleotides Are Not Enougha. Need one more proton to come into the matrix in order for an inorganic phosphate to get inside of the matrix & other 3 protons work the machinery à must invest 4 protons to make 1 ATPb. 104 protons à 26 ATP via ETC made per molecule of glucose plus 4 ATPs made during substrate level phosphorylation à 30 ATP made per one molecule of glucosec. 26 ATP (ETC) + 2 (Glycolysis) + 2 (TCA) = 30 ATP per molecule of
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