光合作用英文版Photosynth.ppt

Almostallplantsarephotosyntheticautotrophs,asaresomebacteriaandprotists,AutotrophsgeneratetheirownorganicmatterthroughphotosynthesisSunlightenergyistransformedtoenergystoredintheformofchemicalbonds,(a)Mosses,ferns,andfloweringplants,(b)Kelp,(c)Euglena,(d)Cyanobacteria,THEBASICSOFPHOTOSYNTHESIS,LightEnergyHarvestedbyPlants&OtherPhotosyntheticAutotrophs,6CO2+6H2O+lightenergyC6H12O6+6O2,WHYAREPLANTSGREEN?,PlantCellshaveGreenChloroplasts,Thethylakoidmembraneofthechloroplastisimpregnatedwithphotosyntheticpigments(i.e.,chlorophylls,carotenoids).,Chloroplastsabsorblightenergyandconvertittochemicalenergy,Light,Reflectedlight,Absorbedlight,Transmittedlight,Chloroplast,THECOLOROFLIGHTSEENISTHECOLORNOTABSORBED,Photosynthesisistheprocessbywhichautotrophicorganismsuselightenergytomakesugarandoxygengasfromcarbondioxideandwater,ANOVERVIEWOFPHOTOSYNTHESIS,Carbondioxide,Water,Glucose,Oxygengas,PHOTOSYNTHESIS,TheCalvincyclemakessugarfromcarbondioxideATPgeneratedbythelightreactionsprovidestheenergyforsugarsynthesisTheNADPHproducedbythelightreactionsprovidestheelectronsforthereductionofcarbondioxidetoglucose,Light,Chloroplast,Lightreactions,Calvincycle,NADP,ADP+P,ThelightreactionsconvertsolarenergytochemicalenergyProduceATP&NADPH,ANOVERVIEWOFPHOTOSYNTHESIS,PHOTOSYNTHESIS,SunlightprovidesENERGY,CO2+H2OproducesGlucose+Oxygen,6CO2+6H2OC6H12O6+6O2,StepsofPhotosynthesis,Lighthitsreactioncentersofchlorophyll,foundinchloroplasts,Chlorophyllvibratesandcauseswatertobreakapart.,Oxygenisreleasedintoair,HydrogenremainsinchloroplastattachedtoNADPH“THELIGHTREACTION”,StepsofPhotosynthesis,TheDARKReactions=CalvinCycle,CO2fromatmosphereisjoinedtoHfromwatermolecules(NADPH)toformglucose,Glucosecanbeconvertedintoothermoleculeswithyummyflavors!,Inmostplants,photosynthesisoccursprimarilyintheleaves,inthechloroplastsAchloroplastcontains:stroma,afluidgrana,stacksofthylakoidsThethylakoidscontainchlorophyllChlorophyllisthegreenpigmentthatcaptureslightforphotosynthesis,Photosynthesisoccursinchloroplasts,Thelocationandstructureofchloroplasts,LEAFCROSSSECTION,MESOPHYLLCELL,LEAF,Chloroplast,Mesophyll,CHLOROPLAST,Intermembranespace,Outermembrane,Innermembrane,Thylakoidcompartment,Thylakoid,Stroma,Granum,Stroma,Grana,Chloroplastscontainseveralpigments,ChloroplastPigments,ChlorophyllaChlorophyllbCarotenoidsXanthophyll,Figure7.7,Chlorophylla&b,ChlahasamethylgroupChlbhasacarbonylgroup,Differentpigmentsabsorblightdifferently,CyclicPhotophosphorylationProcessforATPgenerationassociatedwithsomePhotosyntheticBacteriaReactionCenter=700nm,Photon,Photon,Water-splittingphotosystem,NADPH-producingphotosystem,ATPmill,Twotypesofphotosystemscooperateinthelightreactions,NoncyclicPhotophosphorylationPhotosystemIIregainselectronsbysplittingwater,leavingO2gasasaby-product,TheO2liberatedbyphotosynthesisismadefromtheoxygeninwater(H+ande-),PlantsproduceO2gasbysplittingH2O,TwoconnectedphotosystemscollectphotonsoflightandtransfertheenergytochlorophyllelectronsTheexcitedelectronsarepassedfromtheprimaryelectronacceptortoelectrontransportchainsTheirenergyendsupinATPandNADPH,Inthelightreactions,electrontransportchainsgenerateATP,NADPH,&O2,TheelectrontransportchainsarearrangedwiththephotosystemsinthethylakoidmembranesandpumpH+throughthatmembraneTheflowofH+backthroughthemembraneisharnessedbyATPsynthasetomakeATPInthestroma,theH+ionscombinewithNADP+toformNADPH,ChemiosmosispowersATPsynthesisinthelightreactions,2H+1/2,Water-splittingphotosystem,Reaction-centerchlorophyll,Light,Primaryelectronacceptor,Energytomake,Electrontransportchain,Primaryelectronacceptor,Primaryelectronacceptor,NADPH-producingphotosystem,Light,NADP,1,2,3,HowtheLightReactionsGenerateATPandNADPH,TheproductionofATPbychemiosmosisinphotosynthesis,Thylakoidcompartment(highH+),Thylakoidmembrane,Stroma(lowH+),Light,Antennamolecules,Light,ELECTRONTRANSPORTCHAIN,PHOTOSYSTEMII,PHOTOSYSTEMI,ATPSYNTHASE,SummaryLightDependentReactions,a.Overallinputlightenergy,H2O.b.OveralloutputATP,NADPH,O2.,AnimationisoftheCalvinCycleNotewhathappenstothecarbondioxideandwhattheendproductis.SecondanimationoftheCalvinCycleisveryclearandevendoesthemolecularbookkeepingforyou.,LightIndependentReactionsakaCalvinCycle,CarbonfromCO2isconvertedtoglucose(ATPandNADPHdrivethereductionofCO2toC6H12O6.),LightIndependentReactionsakaCalvinCycle,CO2isaddedtothe5-CsugarRuBPbytheenzymerubisco.Thisunstable6-CcompoundsplitstotwomoleculesofPGAor3-phosphoglycericacid.PGAisconvertedtoGlyceraldehyde3-phosphate(G3P),twoofwhichbondtoformglucose.G3Pisthe3-Csugarformedbythreeturnsofthecycle.,SummaryLightIndependentReactions,a.OverallinputCO2,ATP,NADPH.b.Overalloutputglucose.,Review:Photosynthesisuseslightenergytomakefoodmolecules,Light,Chloroplast,PhotosystemIIElectrontransportchainsPhotosystemI,CALVINCYCLE,Stroma,Electrons,LIGHTREACTIONS,CALVINCYCLE,Cellularrespiration,Cellulose,Starch,Otherorganiccompounds,Asummaryofthechemicalprocessesofphotosynthesis,TypesofPhotosynthesis,C3C4CAM,Rubisco:theworldsbusiestenzyme!,CompetingReactions,RubiscograbsCO2,“fixing”itintoacarbohydrateinthelightindependentreactions.O2canalsoreactwithrubisco,inhibitingitsactivesitenotgoodforglucoseoutputwastestimeandenergy(occupiesRubisco),Photorespiration,WhenRubiscoreactswithO2insteadofCO2Occursunderthefollowingconditions:IntenseLight(highO2concentrations)HighheatPhotorespirationisestimatedtoreducephotosyntheticefficiencyby25%,Whyhighheat?,Whenitishot,plantsclosetheirstomatatoconservewaterTheycontinuetodophotosynthesisuseupCO2andproduceO2createshighO2concentrationsinsidetheplantphotorespirationoccurs,C4Photosynthesis,CertainplantshavedevelopedwaystolimittheamountofphotorespirationC4Pathway*CAMPathway*BothconvertCO2intoa4carbonintermediateC4Photosynthesis,LeafAnatomy,InC3plants(thosethatdoC3photosynthesis),allprocessesoccurinthemesophyllcells.,Imagetakenwithoutpermissionfrom,C4Pathway,InC4plantsphotosynthesisoccursinboththemesophyllandthebundlesheathcells.,Imagetakenwithoutpermissionfrom,C4Pathway,CO2isfixedintoa4-carbonintermediateHasanextraenzymePEPCarboxylasethatinitiallytrapsCO2insteadofRubiscomakesa4carbonintermediate,C4Pathway,The4carbonintermediateis“smuggled”intothebundlesheathcellThebundlesheathcellisnotverypermeable