生物化學chaprespirationandenergy的學習材料

生物化學chaprespirationandenergy的學習材料第1頁/共16頁(2)Energyyield(3)Physiologicalimportance(1)biochemicalreactionsCO2NADHFADHNADPH電子傳遞鏈H2OATP第2頁/共16頁Electrontransportandoxidativephosphorylationre-oxidizeNADHand

FADH2andtraptheenergyreleasedasATP.Introduction第3頁/共16頁Ineukaryotes(真核細胞),electrontransportandoxidativephosphorylationoccurintheinnermembraneofmitochondria(線粒體),whereasinprokaryotes(原核生物)theprocessoccursintheplasmamemebrane.attention第4頁/共16頁

ConceptElectrontransportchain(respiratorychain)consistsofaseriesofelectroncarriersbywhichelectronsaretransferredfromNADH(FADH2)

tooxygen.Electron-transportchain第5頁/共16頁琥珀酸脫氫酶(黃素脫氫酶類)NAD脫氫酶輔酶Q細胞色素類2H＋第6頁/共16頁

Mainparts(enzyme)NADHdehydrogenase(NADH-Qreductase)Succinate-CoQ(琥珀酸鹽輔酶Q)reductaseCytochromebc1reductaseCytochromecoxidase

Twosmallelectroncarriersareneeded:Ubiquinone(coenzymeQ,CoQ);cytochromec第7頁/共16頁

ConceptOxidativephosphorylationisthenamegiventothesynthesisofATP(phosphorylation)thatoccurswhenNADHandFADH2areoxidizedbyelectrontransportthroughtherespiratorychain(oxidation).Oxidativephosphorylation第8頁/共16頁Unlikesubstratelevelphosphorylation,itdoesnotinvolvephosphorylatedchemicalinermediates.Rather,theenergythatliberatedbyelectrontransport

isusedtodrivethesynthesisofATPfromADPandPi(catalyzedbyATPsynthase)..attention第9頁/共16頁substratelevelphosphorylation

底物水平磷酸化有機物氧化過程中由于底物分子內(nèi)部能量重新分布形成高能磷酸鍵，轉(zhuǎn)給ADP形成ATP。第10頁/共16頁

thesequenceoftransportalloftheelectroncarriersinthetransportchaininteractaccordingtotheirredoxpotentials(還原力).Everytimethatanelectrontransferoccurs,theacceptingcarrierhasahigheraffinityforelectronsthanthedonatingcarrier.ThusthereisanetflowofelectronfromNADHtooxygen.第11頁/共16頁

ThepositionofATPsynthesis氧化還原電位（E0’）：pH7.0，30℃測得。表征物質(zhì)得失電子趨勢。電子總是從低氧化還原電位流向高電位。E0’越低，供電子傾向越大。?G：?0，表示反應是自發(fā)過程。－?G＝nF?U＝n×96487×（E02’－E01’）?30.5kJ第12頁/共16頁第13頁/共16頁

AmountsofATP

P/O:thenumberofPiusedWhenoneoxygenatomisoxidizedtogenerateH2O.

NADH+H++3ADP+3Pi+1/2O2NAD++4H2O+3ATPFADH2+2ADP+2Pi+1/2O2NAD++3H2O+2ATP第14頁/共16頁

ThemechanismofATPsynthesis

Chemiosmotichypothesis(化學滲透假說)

Thisproposesthatenergyliberatedbyelectrontransportisusedtocreateaprotongra