Cellular Respiration. Cellular Respiration = Glucose Oxidation.

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    25-Dec-2015

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<ul><li> Slide 1 </li> <li> Cellular Respiration </li> <li> Slide 2 </li> <li> Cellular Respiration = Glucose Oxidation </li> <li> Slide 3 </li> <li> Redox Reactions </li> <li> Slide 4 </li> <li> Coenzyme NAD+ is an electron carrier NAD + - oxidized NADH + H + - reduced </li> <li> Slide 5 </li> <li> NADH -Nicotinamide adenine dinucleotide Coenzyme found in all cells Made of 2 nucleotides </li> <li> Slide 6 </li> <li> Slide 7 </li> <li> Mitochondrial structure - label </li> <li> Slide 8 </li> <li> Mitochondrial structure </li> <li> Slide 9 </li> <li> Cellular Respiration overview Process Starting Molecule End product LocationSubstrate level phosphor ylation Energy shuttled to oxidative phosphor ylation Glycolysis1 glucose2 pyruvate Cytosol2 ATP2 NADH (intermed iate step) 2 pyruvate 2 Acetyl Co-A, 2 CO 2 Matrix of mitochon dria None2 NADH </li> <li> Slide 10 </li> <li> Slide 11 </li> <li> Totals entering oxidative phosphorylation: 4 ATP from substrate phosphorylation 10 NADH (2 from glycolysis) 2 FADH 2 </li> <li> Slide 12 </li> <li> NADH from glycolysis 2 ATP (need 1 to shuttle NADH into mitochondria) NADH 3 ATP FADH 2 2 ATP This is theoretical yield Total energy produced = 36 38 ATP molecules - 2 in glycolysis, 2 in Krebs, 32-34* in Oxidative phosphorylation * 34 for plants (dont spend an ATP to get NADH into mitochondria), 32 for animals </li> <li> Slide 13 </li> <li> Glycolysis Glyco glucoseLysis - splitting or breaking Pg. 162-163 How is glucose split? </li> <li> Slide 14 </li> <li> Glycolysis summary How many reactions are required? What catalyzes each reaction? How many ATP are produced? How many net ATP are produced? What is the initial reactant? What are the final products? Where does this occur in the cell? </li> <li> Slide 15 </li> <li> Glycolysis </li> <li> Slide 16 </li> <li> Glycolysis summary How many reactions are required? 10 What catalyzes each reaction? Specific enzyme How many ATP are produced? 4 How many net ATP are produced? 2 What is the initial reactant? glucose What are the final products? Pyruvate, 2 ATP, 2 NADH Where does this occur in the cell? cytosol </li> <li> Slide 17 </li> <li> Krebs cycle (aka citric acid cycle) What is the starting molecules for the Krebs cycle? What was the ending molecules of glycolysis? </li> <li> Slide 18 </li> <li> Slide 19 </li> <li> Krebs cycle (aka citric acid cycle) What is the starting molecules for the Krebs cycle? Acetyl CoA What was the ending molecules of glycolysis? pyruvate </li> <li> Slide 20 </li> <li> Pyruvate to Acetyl CoA Intermediate step: pyruvate oxidation How many reactions needed to convert pyruvate to acetyl CoA? What is lost in the process? What is gained in the process? Where does this occur? </li> <li> Slide 21 </li> <li> Slide 22 </li> <li> Pyruvate to Acetyl CoA Intermediate step: pyruvate oxidation How many reactions needed to convert pyruvate to acetyl CoA? 3 What is lost in the process? CO 2, electron to NAD+ What is gained in the process? NADH, Acetyl CoA Where does this occur? As pyruvate enters mitochondrion, in the mitochondrial matrix </li> <li> Slide 23 </li> <li> Krebs Cycle 1 st step In first step: Oxaloacetate (4 C) + Acetyl-CoA (2 C) yields citrate (6 C) Oxaloacetate gets regenerated through Krebs cycle -ate conjugate bases of the organic acids Carboxyl groups can donate protons i.e. citrate is the conjugate base of citric acid </li> <li> Slide 24 </li> <li> Krebs cycle p. 165 How many reactions? What catalyzes these reactions? How many ATP produced? How are the ATP produced? Where does the rest of the energy harvested go? </li> <li> Slide 25 </li> <li> Krebs Cycle </li> <li> Slide 26 </li> <li> Slide 27 </li> <li> Krebs cycle How many reactions? 8 What catalyzes these reactions? Specific enzymes How many ATP produced? 1 per cycle (2 total) How are the ATP produced? Substrate phosphorylation Where does the rest of the energy harvested go? Electron carriers: 3 NADH, 1 FADH 2 per cycle (6 NADH, 2FADH 2 total) </li> <li> Slide 28 </li> <li> Krebs cycle How many turns of the cycle for 1 molecule glucose? What are the initial reactants? Final products? Where does this occur? </li> <li> Slide 29 </li> <li> Krebs cycle How many turns of the cycle for 1 molecule glucose? 2 since glucose splits into 2 pyruvate What are the initial reactants? Final products? Initial: 2 Acetyl CoA, 6 NAD+, 2 FAD, 2 ADP Final: 4 CO 2, 6 NADH, 2FADH 2, 2 ATP Where does this occur? In the mitochondrial matrix </li> <li> Slide 30 </li> <li> Substrate level phosphorylation </li> <li> Slide 31 </li> <li> Substrate Level Phosphorylation As each bond of glucose is broken, energy is released: If enough energy released all at once, the energy is used to directly phosphorylate ADP to make ATP (substrate level phosphorylation) </li> <li> Slide 32 </li> <li> -- If amount of energy released is small, electrons are taken off as units of energy and handed to an electron shuttle, NADH NADH gathers all the electrons and passes them off to the electron transport chain, so they can make ATP through oxidative phosphorylation </li> <li> Slide 33 </li> <li> Oxidative Phosphorylation: Electron Transport Chain &amp; Chemiosmosis Electron Transport Chain see diagram on handout Where do the electrons for the electron transport chain come from? Why are electrons transferred from carrier to carrier? Why does FADH 2 enter at a different point than NADH? </li> <li> Slide 34 </li> <li> Slide 35 </li> <li> Electron Transport Chain/Oxidative Phosphorylation Electron Transport Chain see diagram on handout Where do the electrons for the electron transport chain come from? From glycolysis, intermediate, krebs Why are electrons transferred from carrier to carrier? Transferred to more electronegative carrier Why does FADH 2 enter at a different point than NADH? Has higher electronegativity </li> <li> Slide 36 </li> <li> What atom is the final acceptor of the electron? Why? What does it form? What is gained during this process? </li> <li> Slide 37 </li> <li> What atom is the final acceptor of the electron? oxygen Why? Most electronegative What does it form? water What is gained during this process? A H+ gradient </li> <li> Slide 38 </li> <li> Oxidative phosphorylation What is the purpose? What is a chemiosmotic gradient? How does this generate ATP? </li> <li> Slide 39 </li> <li> Oxidative phosphorylation What is the purpose? To produce ATP from ADP What is a chemiosmotic gradient? A difference in concentration of H+ ions across a membrane (can be used to do work) How does this generate ATP? Flow of H+ ions through ATP synthase into mitochondrial matrix cause the ATP synthase to rotate- chemical energy converted to mechanical energy This drives phosphorylation of ADP into ATP (ADP + inorganic phosphate) </li> <li> Slide 40 </li> <li> ATP Synthase Uses flow of hydrogen ions down gradient to form ATP from inorganic phosphate and ADP </li> <li> Slide 41 </li> <li> ATP synthase video http://www.dnatube.com/video/104/ATP- synthase-structure-and-mechanism http://www.dnatube.com/video/104/ATP- synthase-structure-and-mechanism </li> <li> Slide 42 </li> <li> Cellular Respiration </li> <li> Slide 43 </li> <li> ATP Numbers... Not exact Based on experimental data- 1 molecule glucose yields 29 ATP NADH 2.5 ATP, FADH 2 1.5 ATP NADH from glycolysis in cytosol electrons get passed to NAD+ or FAD in mitochondrial matrix (which carrier makes a difference in total ATP) Also some of the proton motive force powers mitochondrions uptake of pyruvate from cytosol, also transport of phosphate into mit. matrix </li> <li> Slide 44 </li> <li> Cellular respiration efficiency about 40% of energy from glucose gets stored in ATP The rest of the energy is lost as heat </li> <li> Slide 45 </li> <li> Thermoregulation Reducing efficiency of cellular respiration Hibernating mammals need to maintain body temperature Have a channel protein in inner mitochondrial membrane that allows protons to flow back down concentration gradient without generating ATP Allows for oxidation of fats to generate heat without ATP production </li> <li> Slide 46 </li> <li> If oxygen is not present, etc and oxidative phosphorylation cant occur 2 ways to produce ATP: Anaerobic respiration prokaryotic organisms in environment without oxygen Use another final electron acceptor rather than oxygen, i.e. sulfur Fermentation ATP without oxygen </li> <li> Slide 47 </li> <li> Makes ATP through glycolysis (only 2 ATP) NADH transfers its electrons to pyruvate, so NAD+ can be used again in glycolysis Alcoholic fermentation pyruvate converted to ethyl alcohol and CO 2 Lactic acid fermentation pyruvate converted to lactate Fermentation </li> <li> Slide 48 </li> <li> Slide 49 </li> <li> What about prokaryotes? Glycolysis cytosol Krebs cycle cytosol Electron transport chain electron carriers in plasma membrane, gradient gets generated across plasma membrane Do not need to transport electrons (in NADH) from glycolysis into mitochondria, so can get more ATP </li> <li> Slide 50 </li> <li> Evolution &amp; Glycolysis Glycolysis is widespread among organisms Oldest fossils of bacteria 3.5 billion years old O 2 in atmosphere not until 2.7 billion years ago Perhaps early cells got ATP just through glycolysis </li> <li> Slide 51 </li> <li> Food Catabolism Proteins, Carbohydrates &amp; Fats can all be used by cellular respiration to make ATP Biosynthesis Intermediates in the pathway of cell. resp. can be used to synthesize molecules for the cell. </li> <li> Slide 52 </li> <li> Control of cellular respiration Phosphofructokinase Enzyme that catalyzes 3 rd step of glycolysis - commitment step for glycolysis Allosteric enzyme Inhibited by ATP, citrate Stimulated by AMP </li> </ul>

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