Cellular Respiration Energy Conversion. Why? Convert energy to forms usable by cells – Chemical bond energy  ATP energy – ATP via chemiosmosis; NADH

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Cellular Respiration

Cellular RespirationEnergy ConversionWhy?Convert energy to forms usable by cellsChemical bond energy ATP energyATP via chemiosmosis; NADH via redox reactionElectron transportElectrochemical proton concentration gradientHave store of ATP & NADH molecules availableDrive cellular processesTransportation of metabolites, organelles, etcLocomotion of cellSynthesizing complex molecules

ATP = adenosine triphosphateAdenosineAdenine = nitrogenous purine base Ribose = a cyclic 5-carbon sugarTriphosphatePhosphate is negatively charged polyatomic ionPlacing phosphates near each other requires workEnergy of electrostatic repulsion is stored in bondBroken bond releases energy for doing workWho?Aerobic bacteriaAll aerobic eukaryotic organisms1000 to 2000 mitochondria in each liver cellMitochondria associated with microtubulesMay move in cytoplasm or be fixed in locationConcentrated in areas of high energy demandsForm long chains with each otherWrapped around flagellumPacked between cardiac myofibrils

Where?Mitochondrion is site of oxidative respirationMitochondria have double membranesInner vs. outer membraneOuter membrane has transport proteins & large poresInner membrane is selectively permeable; forms cristaeMembranes create 2 internal compartmentsMatrix is inside organelleEnzyme-rich mixture, mDNA, ribosomes, tRNA, etcIntermembrane space is between membranes.Site of ATP synthesisWhen?Begins when large amounts of acetyl coenzyme A (acetyl CoA)are produced in the matrix spaceMajor fuel is acetyl CoA from pyruvate usuallyStores of fatty acids & glycogen fuel processFats are stored in adipose tissue (fuel for 1 month)Glycogen/ glucose is stored in liver (fuel for 1 day)Glucose via glycolysis yields pyruvateWhen else?Fats can be broken down into fatty acids and glycerolGlycerol broken down in glycolysis to pyruvateFatty acids broken down into 2-C fragmentProteins can be broken down into amino acidsCertain amino acids can lose NH3 to form pyruvateSome amino acids minus NH3 form 2-C fragmentPyruvate/2-C fragment (acetyl CoA) enters mitochondria for citric acid cycleHow?GlycolysisSugar is broken down into pyruvic acid + 2 ATPCitric acid cycle (Krebs cycle)Acetyl CoA from pyruvate enters cycleH2O supplies extra O2 & H+2 CO2 + 2 NADH + FADH2 + 2 GTP exitElectron transport chainElectrons from NADH move down chain26 ATP formed via ATP synthase

Anaerobic: Step 1GlycolysisC6H12O6 2 C3H3O3- + 2 ATP + 2 NADH (net)Glucose via 9 steps is broken down into 2 pyruvates

3-C Pyruvate 2-C acetyl CoA + CO2

Citric Acid Cycle: Step 2Citric acid cycle (Krebs cycle) in matrixPyruvate Acetyl CoA + CO2 + NADHAcetyl CoA enters Krebs cycleKrebs has 8 enzymatic reactions that harvest electronsNAD+ accepts electrons NADH carries electronsCO2 + electrons (NADH + FADH2) + 2 ATP & H+ movement are end productsElectron Transport ChainOxidative phosphorylationIn inner mitochondrial membraneElectrons are delivered by NADHElectrons move down chain of proteinsH+ build up in mitochondrial intermembrane space due to movement of electronsATP synthase is powered by H+ movement across membrane 26 ATP are produced O2 + 2 H+ H2O {oxygen is final electron acceptor)Final CountGlucose + oxygen carbon dioxide + water + 38 ATP


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