Chapter 9 - Cellular RespirationFriday, October 16, 20158:12 AM Fermentation and Cellular Respiration-Fermentation - without oxygen-Cellular respiration - with oxygen Cellular respiration:C6H12O6 ----------> 6CO2 + 6H2O + Energy (ATP + heat) -The breakdown of glucose to CO2 +H2O is exergonic-Has free energy change G = -686 kcal/mol-Involves oxidation-reduction reaction Redox-Oxidation is always coupled to reduction - they occur togetherX(e-) + Y ---------> X + Y(e-)oOxidizing agent - becomes reducedoReducing agent - becomes oxidizedNa + Cl ---------> Na+ + Cl-oLEO SAYS GER-LEO: Lose Electrons Oxidation-Na ---------> (Na+) + (e-) Sodium is oxidized-GER: Gain Electrons ReductionoDiscussing the reactants Electronegative Elements-Trend - increase left to right, bottom to top-Higher potential energy Combustion (lots of energy)-Redox reaction - presence of electron movementCH4 + 2O2 ----------> CO2 + Energy + 2H2O-Electrons are moving toward oxygen - (oxygen gain electrons and being reduced) Extraction of Energy from Glucose During Cellular Respiration-Cellular respirationC6H12O6 ----------> 6CO2 + 6H2O + Energy (ATP + heat)oCarbon has lower electron affinity - electronegativityoGlucose - low electron affinityoOxygen - high electron affinityoGlucose oxidized to carbon dioxideoOxygen reduced to water-Glucose = high potential energy molecule (C-H bonds include electrons in covalent bonds with lower polarity)-Carbon dioxide = low potential energy (C-O bonds include electrons in covalent bonds with higher polarity)-Potential energy of molecule = potential energy of molecule Q1. When electrons move closer to a more electron negative atom,a. Energy is consumedb. Energy is releasedc. The more electron negative atom is oxidizedd. The more electron negative atom is reduced (gained atom)e. B and D only Electron movement is from hydrogenNAD > NADH -Glycolysis (sugar/split)oNAD+/ADP, split glucoseoInto 2 pyruvate, ATP NADHoTakes place in cytoplasm-Citric acid cycleo2 pyruvate into 6 carbon dioxide (CO2)oReduced forms of electron carriers (NADH FADH2) carrying electrons with high potential energyoTakes place in mitochondria-Carry onto electron transport chain (ETC)oRequires oxygenoApproximately 36/38 ATPoTakes place in mitochondria cristae, inner membrane of mitochondria Where are the citric acid cycle and oxidative phosphorylation happening 1 Glucose split into 2 pyruvateATP producedOxidized glucose - electron carriers generated via NADH Pyruvate completely oxidized into CO2 within citric acid cycleElectron carriers Reduced form of electron carriers will be delivered to ETC where electrons will be stripped electron potential energy will be used to produce more ATP Purpose of All these processes-This is catabolic metabolism-The purpose is to convert the potential energy of glucose into the potential energy of ATP to do cellular work-CO2 - low potential energy - CO bond so close to …-As glucose turns into carbon dioxide, captured by ATP, used to synthesize ATP Glycolysis-Contains 10 enzyme-catalyzed chemical reactions in sequenceoInput: 2 ATP, 2 NAD+, glucoseoOutput: 2 molecules of pyruvate, 2 NADH, 4 ATP-NET GAIN of ATP = 2 ATP (how many ATP produced from glycolysis)o2 steps-Energy Investment Phase-Energy Payoff Phase - harvest ATPoATP produced within substrate level phosphorylation-Bookkeepingo2 ATP were invested in first phase of glycolysiso4 ATPs per original glucose producedi n 2nd phaseo2 molecules of NADH also producedoGlycolysis INVEST 2 ATP > produce 4 ATP = Net 2 ATP 2 NADH-Substrate level phosphorylationoOrganic phosphate attached-Energy yield from glycolysisoGlucose > 6 CO2 = -686 kcal/moleo2 ATPs produced (2 x 7.3 = 14.6 14.6 kcal/moleoEnergy yield 14.6/686 = 0.0213 2% recovered as ATPoSubsequent oxidation of pyruvate and NADH can recover more of the free energy from glucose Citric Acid Cycle Q4. How many carbon dioxide molecules from 2 pyruvate, 4 rounds?o8 For each glucose that enters glycolysis we have a net gain of -4 ATP moleculeso2 from glycolysiso2 from citric acid cycle-10 NADH moleculeso2 from glycolysiso2 from conversion of pyruvate to acetyl Co-A (strip carbon from pyruvate)o6 from the oxidation of acetyl Co-A in the citric acid cycle-2FADH2 moleculeso2 from the citric acid cycle-6CO2 moleculeso2 from the conversion of pyruvate to acetyl Co-Ao4 from the oxidation of acetyl Co-A in the citric acid cycle-(what is produced rom citric acid cycle)-(what is produced from two molecules of glucose) Q.5 For every 5 molecules of glycose metabolized through glycolysis and citric acid cycle, how many NADH will be produced?o50 Electron transport chains allow for a controlled release of energyUncontrolled reaction H2 + 1/2 O2---------------------->Explosive release of heat and light energyH2O -The electrons carried on the NADH and FADH2 are passed to a chain of protein-metal complexes = called electron transport chainoEnter ETC from different positionsoNADH enter with higher potential energy - enter from the very beginning of ETCoFADH enters within the middle of ETCoAs you go down, higher electronegativity-That's why it is possible for electrons to move down-Work as proton pumps across the membraneoDecreases as they pass through-Intermembrane space - higher protein concentration-Inner mitochondrial membrane-Mitochondrial matrix - lower protein concentration-Membrane is not permeable to proton-Make a concentration protein difference across the membrane and that difference has potential energy - proton motive forceoDrives ATP synthesisMitochondrial matrixATP synthase has two partsIntermembrane space - allows proton to move throughRotor - works as ATP synthase, catalyze real ATP synthesis, drive ATP synthesis Oxidative phosphorilation - ATP made from ADP Grab one substrate to anotherHere, use inorganic phosphate Each NADH can produce 2.5 ATPEach FADH can produce 1.5 ATP7.3 x 38 / 686 = 40%, the rest of the energy are relased as heat Aerobic cell. Resp. - most effective way of energy conversionHarvest most energy from molecule glucoseQ6. (location/input/output) Where are the proteins of ETC located?-Inner membrane of mitochondriaQ7. How many ATP are produced per second per cell -10 million Fermentation-No oxygen present-Pyruvate oxidizes NAD > NADH-Manage a way to produce pyruvate and NAD+ to keep glycolysis going Fuel Available for Catabolic Reactions-Main pathway of the cell to obtain energyoCarbohydrates converted to glucose and goes through glycolysisoProtein chopped down into