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Chapter 7 intro



  • Cellular respirationProcess by which living cells obtain energy from organic moleculesPrimary aim to make ATP and NADHAerobic respiration uses oxygenO2 consumed and CO2 releasedOrganic molecules + O2 CO2 + H2O + EnergyGlucose metabolism4 metabolic pathwaysGlycolysis Breakdown of pyruvate to an acetyl groupCitric acid cycleOxidative phosphorylation

  • Stage 1: GlycolysisGlycolysis can occur with or without oxygenSteps in glycolysis nearly identical in all living species10 steps in 3 phasesEnergy investmentCleavageEnergy liberation

  • 3 phases of glycolysisEnergy investment primingSteps 1-32 ATP hydrolyzed to create fructose-1,6 bisphosphateCleavageSteps 4-56 carbon molecule broken into two 3 carbon molecules of glyceraldehyde-3-phosphateEnergy liberationSteps 6-10Two glyceraldehyde-3-phosphate molecules broken down into two pyruvate molecules producing 2 NADH and 4 ATPNet yield in ATP of 2

  • Stage 2: Breakdown of pyruvate to an acetyl group In eukaryotes, pyruvate in transported to the mitochondrial matrixBroken down by pyruvate dehydrogenaseMolecule of CO2 removed from each pyruvateRemaining acetyl group attached to CoA to make acetyl CoA1 NADH is made for each pyruvate

  • Regulating aerobic respirationControl of glucose catabolism occurs at three key points in the catabolic pathway. -Glycolysis- phosphofructokinase, pyruvate oxidation-pyruvate decarboxylase and krebs cycle- citrate syntehetaseCompetitive inhibition: Krebs cycle, oxaloacetate- inhibitor, enzyme- succinate dehydrogenase. Prevents making fumerate.

  • Stage 3: Citric acid cycle/ krebs cycle/ tricarboxyclyic acid cycleMetabolic cycleParticular molecules enter while other leave, involving a series of organic molecules regenerated with each cycleAcetyl is removed from Acetyl CoA and attached to oxaloacetate to form citrate or citric acidSeries of steps releases 2CO2,and forms 1ATP, 3NADH, and 1 FADH2Oxaloacetate is regenerated to start the cycle again

  • Stage 4: Oxidative phosphorylationHigh energy electrons removed from NADH and FADH2 to make ATPTypically requires oxygenOxidative process involves electron transport chainPhosphorylation occurs by ATP synthaseElectron transport chainGroup of protein complexes and small organic molecules embedded in the inner mitochondrial membraneCan accept and donate electrons in a linear manner in a series of redox reactionsMovement of electrons generates H+ electrochemical gradient/ proton-motive forceExcess of positive charge outside of matrix

  • Free energy changeMovement from NADH to O2 is a very negative free energy changeSpontaneous in forward directionHighly exergonicSome energy used to pump H+ across inner mitochondrial membrane and create H+ electrochemical gradient

  • Theortetical atp yield of aerobic respirtationGlucose is entirel consumed on of the carbons in pyruvate is lost as co2 in the conversion to acetyl coa two other carbons are lost during the oxidations of the krebs cuclee and two molecules of atp make glycolysisTywo more atp molecules have been made in krebsTweleve electron carriers have been reduced 10 nadph and two fadh2 and h has built up so actually yield is 30 molecules of atp1. leaking inner mitchondrial membrane2. h+gradient uptake of pyruvate 3. nadh energy to other molecules 4. atps from substrate phosphory lation 25. nadh 2.5/ 10 molecule 3. fadhs 1.5/2 molecules equals 32 and minus 2 for transport of glycolytic nadh equals 307.3x30/686= 32% efficiency

  • ATP synthaseEnzyme harnesses free energy as H+ flow through membrane embedded regionEnergy conversion- H+ electrochemical gradient or proton motive force converted to chemical bond energy in ATPRacker and Stoeckenius confirmed ATP uses an H+ electrochemical gradientRotary machine that makes ATP as it spins

  • Yoshida and Kinosita demonstrated that the subunit of the ATP synthase spinsMasasuke Yoshida, Kazuhiko Kinosita, and colleagues set out to experimentally visualize the rotary nature of the ATP synthaseReleased membrane embedded portion and adhered it to a slideVisualize g subunit using fluorescenceAdded ATP to make reaction run backwardRotated counterclockwise to hydrolyze ATPRotate clockwise to synthesize ATP

  • Cancer cells usually favor glycolysisMany disease associated with alterations in carbohydrate metabolismWarburg effect- cancer cells preferentially use glycolysis while decreasing oxidative phosphorylation {18F] fluorodeoxyglucoseUsed to diagnose cancers in PET scansGlycolytic enzymes overexpressed in 80% of all types of cancersCaused by genetic and environmental factors- mutations and low oxygenVon hippel-lindau syndrome-hypoxia

  • Other organic moleculesOther carbohydrates, proteins and fats also used for energyEnter into glycolysis or citric acid cycle at different pointsUtilizing the same pathways for breakdown increases efficiencyMetabolism can also be used to make other molecules (anabolism)

  • Other acceptorsE. coli uses nitrate (NO3-) under anaerobic conditionsMakes ATP via chemiosmosis even under aerobic conditionsAnaerobic metabolismFor environments that lack oxygen or during oxygen deficits2 strategiesUse substance other than O2 as final electron acceptor in electron transport chainProduce ATP only via substrate-level phosphorylation

  • FermentationSome organisms cannot use O2 as final electron acceptorMake ATP via glycolysis onlyNeed to regenerate NAD+ to keep glycolysis runningMuscle cells produce lactateYeast make ethanolProduces far less ATP

  • Secondary MetabolismPrimary metabolism- essential for cell structure and functionSecondary metabolism- synthesis of secondary metabolites that are not necessary for cell structure and growthSecondary metabolites unique to a species or groupRoles in defense, attraction, protection, competition

  • 4 categoriesPhenolics- flavonoids, tannins ,ligninsAntioxidants with intense flavors and smellsAlkaloids- caffeine nicotine atropineBitter-tasting molecules for defenseTerpenoids cinnamon fennel clovesIntense smells and colorsPolyketides derivatives of acetyl and propionyl gorupsChemical weapons,Cure cancer

    Life is fueld by energy*Respiration is how we get energy from organic molecules.Aeroboic needs oxygen cause it is the most electronegative so it recieves the de-energized electronAnarobic and Fermentation both lack oxygen, Anarobic- use inorganic compounds to receive de-energized electron (CO2, SO2). In fermenation an organic compound gets the electron (not de-energized)Glucose is our transport sugarImagine batmobile, start with 6 wheels end w/ 3 wheels on each car when splits, one more accident then there are 2 cars with 2 wheels and then a tow truck with 4 wheels comes in and is taking the two autombiles with 2 wheels to a collision center to get ride of the car. There are 4 wheels left.6 carbons in glucose. This breaks down into 4 pathways. Start with glycolyis (10 steps, free floating enzymes, takes place in the cytosol.) Is also called an evolutionary memory cause it happens from the first organisms that were present on eath. We only get 3.5% energy from glycolysis. We retain it cause it can take place in the presence and absence of oxygen so thats why we have it despite its low energy getting rate.Then we have kreb cycle then going to electron transport chain*We have to prime for cleave. Start with glucose (6c). Hexakinase catalyses and an ATP is used up and made into ADP + P. There we have clu. 6. P. DONT ABREVATE IN HOMEWORK. Undergoes an isomerization. Enzyme is phosphoglucoisomerase. Then we have fructose 6 P**Takes place in mitchrondria matrix*Takes places in mitochondrial matrix. Start with a two carbon carbon, now at the two wheeel tow truck part. Both carbons will be completely broken down this is complete oxidation of glucose. 1 molecule of glucose gives 2 pyravate 2 acetly coA x2 and each do krebs once*Chemistry 1070 and 1170; 1080 and 1180; 2410 and 2430; 2420 and 2440; 3110pchem; 3120; 3140 and 5110 capand one of the lecture-lab combinations, 2310, 2330 or 3210 and 3230, or 3310 and 3330; Mathematics 1210, 1220 or 1410, 1420, plus 2210 and 2240; and Physics 1310 and 1320 are required of all chemistry majors. In order to complete the major, three additional, three-credit courses above the 1000 level are required

    Chemistry2310/2330*, 2500, 3210/3230*, 3310/3330*, 3410, 3830, 3840, 4010, 4020, 4230, 4240, 4990, 5000 CMB2050, 3010, 3110, 4010, 4110, 4130, 4220, 6160 EENS2110, 2120, 3400, 6140, 6210 Math2170, 3050, 3090, 3310, 4060, 4210, 4300, 4410, 6030, 6350, 6370 Physics2350, 2360, 3010, 3740, 4650, 6010, 6020, 6080, 6210*Has a rotary park: bacteriorhodophin- the rotary pump. Pumps portons from outside to inside vesicle and position atp synthase that it will make atp outside the cell in the medium. Atp was only made in the light. Which shows it needs a proton motor force to make atp.*Added actin to a protein embededd in the gamma because the actin can polermize an depolymeraize, form and deform. Cause of this can purify actin and label with flourescent material. Beta subunit makes atp by rotating clockwise. They added atp to the sample which moves the actin filaments to move coutnerclockwise so they betas hydrolyze the atp. *Lots of glycolysis in brain, kidney, and uterus(??) so those are all false positives. But increased in liver, lung, pancreas, can light up if they have cancer. The three enzymes the doctors look for are glyceradhye phosphate dehydrongenase, enolase, pyruvate kinase (all enzymes in energy liberation phase)Rate of division exceeds respiration rate two things can happen, hypoxic conditions and then because of that only glycolysis can run (3.5% efficiency) these enzymes are overexpressed because the genes that regulate the synthesi