大学生物课讲义ppt模板之噬菌体chapter.ppt

Chapter4MembraneFunction,3.MembraneFunction,TransportofMoleculesSignalTransduction,Workingcellsmustcontroltheflowofmaterialstoandfromtheenvironment.Membraneproteinshelpwiththistask,theyarethecustomagentsofthecells.,Herearesomefunctionsofproteinmembranes,CELL1,CELL2,PermeabilityofthePlasmaMembrane,SomemoleculesfreelycrossmembraneWater,small,nonchargedmoleculesWatermayalsouseaquaporinstocrossmembraneOthermoleculescannotuseChannelproteinsCarrierproteinsVesiclesEndocytosisorexocytosis,macromolecule,H2O,protein,+,+,-,-,chargedmoleculesandions,phospholipidmolecule,nonchargedmolecules,CopyrightTheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.,Moleculescanpassthroughthemembranethroughdifferentmechanisms,PassiveTransport:DiffusionAcrossMembranesOsmosisandWaterBalanceActiveTransportExocytosisandEndocytosis:TrafficofLargeMolecules,PassageofMoleculesIntoandOutoftheCell,Diffusionisoneresultofthemovementofmolecules.Moleculestendtospreadintotheavailablespace.Diffusionispassivetransport;NOenergyisneeded.,Moleculescontainheatenergy.Theyvibrateandmovearound.,A.PassiveTransport:DiffusionAcrossMembranes,Anothertypeofpassivetransportisfacilitateddiffusion,thetransportofsomesubstancesbyspecifictransportproteinsthatactasselectivecorridors.,GasescandiffusethroughamembraneOxygenandcarbondioxideenterandexitthisway,CopyrightTheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.,capillary,alveolus,bronchiole,oxygen,O2,O2,O2,O2,O2,O2,O2,O2,O2,O2,O2,O2,SeveralfactorsinfluencetherateofdiffusionTemperatureAstemperatureincreases,therateofdiffusionincreasesPressureElectricalcurrentsMolecularsize,B.OsmosisandWaterBalanceinCells,Osmosisisthepassivetransportofwateracrossaselectivelypermeablemembrane.,OsmosisDiffusionofwateracrossadifferentiallypermeablemembraneDiffusionalwaysoccursfromhighertolowerconcentrationOsmoticpressureisthepressurethatdevelopsinasystemduetoosmosisThegreaterthepossibleosmoticpressure,themorelikelyitisthatwaterwilldiffuseinthatdirection,AhypertonicsolutionHasahigherconcentrationofsolute.AhypotonicsolutionHasalowerconcentrationofsolute.AnisotonicsolutionHasanequalconcentrationofsolute.,WaterBalanceinAnimalCells,Thesurvivalofacelldependsonitsabilitytobalancewateruptakeandloss.,Osmoregulationisthecontrolofwaterbalanceinanimals.,WaterBalanceinPlantCells,Waterbalanceinplantcellsisdifferent.Theyhaverigidcellwalls.Theyareatthemercyoftheenvironment.,C.ActiveTransport:ThePumpingofMoleculesAcrossMembranes,Activetransportrequiresenergytomovemoleculesacrossamembrane.,TransportbyCarrierProteinsCarrierproteinsarespecificCombinewithamoleculeoriontobetransportedacrossthemembraneCarrierproteinsarerequiredfor:FacilitatedTransportActiveTransport,ActiveTransport:,FacilitatedtransportSmallmoleculesthatarenotlipid-solubleMoleculesfollowtheconcentrationgradientEnergyisNOTrequired,CopyrightTheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.,Inside,plasmamembrane,carrierprotein,solute,Outside,ActiveTransportMoleculescombinewithcarrierproteinsOftencalledpumpsMoleculesmoveagainsttheconcentrationgradientEnteringorleavingcellEnergyisrequired,K+,K+,K+,K+,K+,K+,K+,K+,K+,K+,K+,K+,K+,K+,K+,K+,K+,K+,P,P,P,P,Na+,Na+,Na+,Na+,Na+,Na+,Na+,Na+,Na+,Na+,Na+,Na+,Na+,Na+,Na+,Na+,Na+,Na+,Na+,Na+,Na+,Na+,Na+,Na+,Inside,6.Changeinshaperesultsandcausescarriertorelease2K+insidethecell.,carrierprotein,Outside,K+,K+,K+,Na+,Na+,Na+,Na+,ADP,ATP,K+,K+,K+,Na+,Na+,3.Changeinshaperesultsandcausescarriertorelease3Na+outsidethecell.,2.ATPissplit,andphosphategroupattachestocarrier.,4.Carrierhasashapethatallowsittotakeup2K+.,5.Phosphategroupisreleasedfromcarrier.,1.Carrierhasashapethatallowsittotakeup3Na+.,Sodium-PotassiumPump,Diffusion,FacilitatedDiffusion,Osmosis,InsidethecellCytoplasm,PassiveNoenergy,ActiveEnergy,INSUMMARY,ATP,D.ExocytosisandEndocytosis:TrafficofLargeMolecules,Mechanismsthatinvolvefusionwiththeplasmamembraneanduseofvesicles.Exocytosis(ExoExit)Secretessubstancesoutsideofthecell.EndocytosisTakessubstancesinsideofthecell.,Exocytosis,Endocytosis,Inphagocytosis(“cellulareating”),acellengulfsaparticleandpackagesitwithinafoodvacuole.Inpinocytosis(“cellulardrinking”),acell“gulps”dropletsoffluidbyformingtinyvesicles.,Differentendocytosis:,Receptor-mediatedendocytosisistriggeredbythebindingofexternalmoleculestomembraneproteins.,CopyrightTheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.,paramecium,solute,solute,a.Phagocytosis,b.Pinocytosis,vacuole,coatedvesicle,plasmamembrane,coatedpit,c.Receptor-mediatedendocytosis,399.9m,vesicle,vacuoleforming,pseudopodofamoeba,0.5m,vesiclesforming,coatedvesicle,coatedpit,receptorprotein,a(right):EricGrave/Phototake;b(right):DonW.Fawcett/PhotoResearchers,Inc.;c(both):CourtesyMarkBretscher,TheRoleofMem