Ch. 9 Cellular Respiration Notes
Ch. 9 Cellular Respiration Notes BSC2010
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This 6 page Class Notes was uploaded by Vrena Puentes on Friday October 2, 2015. The Class Notes belongs to BSC2010 at Florida State University taught by Steven Marks in Summer 2015. Since its upload, it has received 326 views. For similar materials see Biological Science 1 in Biology at Florida State University.
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Date Created: 10/02/15
10115 Ch 9 Cellular Respiration amp Fermentation Where do cells acquire energy Photosynthetic cells l sunlight Nonphotosynthetic ces l organic macromolecules ex sugars fats proteins They must convert the chemical energy of the macromolecules into ATP ATP l ADP Exergonic Hydrolysis Coupled into an Endergonic reaction Remember to draw info from Ch 6 7 amp 8 General cell structure Specific structure of mitochondria amp chloroplasts Permeabiity of membranes Passive transport exergonic Active transport endergonic Coupe exergonic amp endergonic reactions Enzymes are necessary to promote individual reactions Cataboic pathways yield energy by oxidizing organic fuels Severa processes are central to cellular respiration and related pathways Oxidation Exergonic Respiration Endergonic Redox Reactions Reduction amp Oxidation The transfer of e during chemical reactions releases energy stored in organic molecules Reeased energy used to synthesize ATP e are a different form of energy currency They carry potential energy from one molecule to another chemical reactions that transfer e btwn reactants O L R G oxidation is lost respiration is gained as in electrons Reduction gains electrons but the charge is reduced so more negative When you convert oxygen gas 02 to water H20 you are reducing 02 During ceuar respiration the fuel ex glucose is oxidized and 02 is reduced Stages of Cellular Respiration Harvesting of energy from glucose has 3 stages 1 Glycolysis breaks down glucose into 2 molecules of pyruvate 2 Oxidation of Pyruvate begins the breakdown of pyruvate and feeds into the citric acid cycle 3 Citric acid cycle complete the break down of pyruvate into C02 4 Oxidative phosphorylation responsible for most of the ATP synthesis Glycolysis most ancient part of cellular respiration quotsplitting of sugarsquot breaks down glucose into two molecules of pyruvate s in the cytoplasm Energy investment phase 1st reactions require energy Energy payoff phase Rest of this process is exergonic ATP is produced Produces a little bit of ATP Harvest chemical energy by oxidizing glucose to pyruvate Gycoysis occurs whether or not 02 is present Gucose is oxidized in gycoysis so something has to be reduced NAD oxidative agent NADH reduction Glucose l 2 Pyruvate 2 ATP 2 NADH breaks down pyruvate completely to C02 amp uses an electron transport chain w 02 as a nal electron receptor to generate ATP passes the e stored in NADH to less eectronegative acceptors than 02 Pyruvate is not oxidized any further amp no more ATP is made occurs wo oxygen Converts pyruvate to either lactic acid or ethanol Why convert pyruvate to other molecules when 02 is absent if it doesn t generate anymore ATP Fermentation involves the reduction of pyruvate Consists of gycoysis pus reactions Two common types 1 Alcohol fermentation 2 Lactic acid fermentation Our muscle cells perform fermentation to produce lactic acid during strenuous exercise when more ATP can be generated by cellular respiration There is not enough 02 in the cells to perform cellular respiration In the presence of 02 Oxidation of pyruvate Requires NAD oxidizing agent 2 pyruvates oxidation gtgt2 Acetyl CoA Coenzyme A 2 NAD reduction gtgt2 NADH quot gtgt2 C02 10615 Glycolysis 2 major requirements glucose amp NAD oxidizing agent C6H1206 oxidation gtgt2Pyruvate 2NAD reduction gtgt2NADH 2ATP Absence of 02 fermentation Coenzyme A C21H36N7016P3S Citric Acid Cycle aka Krebs cycle completes the break down of pyruvate to CO2 Oxidized organic fuel derived from pyruvate generating 1 ATP 3 NADH amp 1 FADH2 per turn 2Acety CoA oxid gtgt4C02 6NAD red gtgt6NADH 2FAD red gtgt2FADH2 A 2 ATP Has 8 steps each catalyzed by a speci c enzyme The acetyl group of acetyl CoA joins the cycle by combining w oxaloacetate forming citrate Other 7 steps work on decomposing the citrate back to oxaloacetate making it a cycle Through the rst three stages of cellular respiration only 4 ATP molecules have been produced from the initial glucose molecule In which of the products of these stages is the potential energy to produce more ATP molecules stored The 10NADH and 2FADH2 molecules No 02 was necessary for the citric acid cycle During oxygen debt why would muscle cells choose lactic acid fermentation which produces no ATP over sending the pyruvate molecules to the citric acid cycle 2 more ATP molecules The citric acid cycle doesn t provide a mechanism for oxidizing NADH back to NAD Oxidation Phosphorylation covers electron transport chain provides energy necessary for gtgt synthesis of ATP chemiosmosis Chemiosmosis the movement of H protons across a membrane along their concentration gradient passive transport exergonic Cytoplasm Glycolysis l Pyruvate Mitochondria lntermembrane space 4 E electron transport chain Oxidation of Pyruvate NADH ETC Citric acid cycle FADH2 Chemiosmosis couples electron transport to ATP synthesis NADH and FADH2 account for most of the energy extracted from food These two electron carriers donate electrons to the ETC which powers ATP synthesis through oxidative phosphorylation Electron transport chains get more electronegative as they go It transports H out of the matrix membrane Why do hydrocarbons have so much stored energy CH bonds are unstable bc Carbon amp Hydrogen are not very electronegative They have a loose grip Electrons attached to an atom with a stronger electronegative pool ex Oxygen are more stable amp have less potential energy What are these manageable amounts of energy used for Eectron transfer pump in the electron transport chain causes proteins to pump H from the mitochondrial matrix to the intermembrane space H then moves back across the membrane passing through the protein ATP synthase a transmembrane protein that harnesses the energy released when H ions protons move back across the mitochondrial inner membrane along their concentration g H gradient that emphasizes its capacity to do work The reaction shown is the production of water from gaseous oxygen hydrogen ions and electrons What is the effect of this reaction on proton motive force and the pH in the mitochondrial matrix lncreases proton motive force AND pH During cellular respiration most energy ows in this sequence glucose gt NADH gt electron transport chain gt protonmotive force gt ATP ATP Production Glycolysis 2 ATP Citric Acid Cycle 2 ATP 10 NADH ETC Chemiosmosis 28 ATP 2 FADH2 You have a friend who lost 7 kg of fat on a regimen of strict diet and exercise How did the fat leave his body Released as CO2 and H20 What cellular evolutionary event is most likely responsible for a switch from Fermentation to the Citric Acid Cycle and Oxidative Phosphorylation The introduction of a mitochondria into an animal cell Which will produce more ATP One molecule of fatty acid