大學生物課的講義ppt模板之噬菌體chapter

大學生物課的講義ppt模板之噬菌體chapterChapter4

MembraneFunction3.MembraneFunctionTransportofMoleculesSignalTransductionWorkingcellsmustcontroltheflowofmaterialstoandfromtheenvironment.Membraneproteinshelpwiththistask,theyarethecustomagentsofthecells.HerearesomefunctionsofproteinmembranesCELL1CELL2PermeabilityofthePlasmaMembraneSomemoleculesfreelycrossmembraneWater,small,nonchargedmoleculesWatermayalsouseaquaporinstocrossmembraneOthermoleculescannot–use…ChannelproteinsCarrierproteinsVesiclesEndocytosisorexocytosismacromoleculeH2Oprotein++--chargedmoleculesandionsphospholipidmoleculenonchargedmoleculesCopyright?TheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.MoleculescanpassthroughthemembranethroughdifferentmechanismsPassiveTransport:DiffusionAcrossMembranesOsmosisandWaterBalanceActiveTransportExocytosisandEndocytosis:TrafficofLargeMoleculesPassageofMoleculesIntoandOutoftheCellDiffusionisoneresultofthemovementofmolecules.Moleculestendtospreadintotheavailablespace.Diffusionispassivetransport;NOenergyisneeded.Moleculescontainheatenergy.Theyvibrateandmovearound.A.PassiveTransport:DiffusionAcrossMembranesAnothertypeofpassivetransportisfacilitateddiffusion,thetransportofsomesubstancesbyspecifictransportproteinsthatactasselectivecorridors.GasescandiffusethroughamembraneOxygenandcarbondioxideenterandexitthiswayCopyright?TheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.capillaryalveolusbronchioleoxygenO2O2O2O2O2O2O2O2O2O2O2O2SeveralfactorsinfluencetherateofdiffusionTemperatureAstemperatureincreases,therateofdiffusionincreasesPressureElectricalcurrentsMolecularsizeB.OsmosisandWaterBalanceinCellsOsmosisisthepassivetransportofwateracrossaselectivelypermeablemembrane.OsmosisDiffusionofwateracrossadifferentiallypermeablemembraneDiffusionalwaysoccursfromhighertolowerconcentrationOsmoticpressureisthepressurethatdevelopsinasystemduetoosmosisThegreaterthepossibleosmoticpressure,themorelikelyitisthatwaterwilldiffuseinthatdirectionA

hypertonic

solutionHasahigherconcentrationofsolute.AhypotonicsolutionHasalowerconcentrationofsolute.AnisotonicsolutionHasanequalconcentrationofsolute.WaterBalanceinAnimalCellsThesurvivalofacelldependsonitsabilitytobalancewateruptakeandloss.Osmoregulationisthecontrolofwaterbalanceinanimals.WaterBalanceinPlantCellsWaterbalanceinplantcellsisdifferent.Theyhaverigidcellwalls.Theyareatthemercyoftheenvironment.C.ActiveTransport:

ThePumpingofMoleculesAcrossMembranesActivetransportrequiresenergytomovemoleculesacrossamembrane.TransportbyCarrierProteinsCarrierproteinsarespecificCombinewithamoleculeoriontobetransportedacrossthemembraneCarrierproteinsarerequiredfor:FacilitatedTransportActiveTransportActiveTransport:FacilitatedtransportSmallmoleculesthatarenotlipid-solubleMoleculesfollowtheconcentrationgradientEnergyisNOTrequiredCopyright?TheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.InsideplasmamembranecarrierproteinsoluteOutsideActiveTransportMoleculescombinewithcarrierproteinsOftencalledpumpsMoleculesmoveagainsttheconcentrationgradientEnteringorleavingcellEnergyisrequiredK+K+K+K+K+K+K+K+K+K+K+K+K+K+K+K+K+K+PPPPNa+Na+Na+Na+Na+Na+Na+Na+Na+Na+Na+Na+Na+Na+Na+Na+Na+Na+Na+Na+Na+Na+Na+Na+Inside6.Changeinshaperesultsandcausescarriertorelease2K+insidethecell.carrierproteinOutsideK+K+K+Na+Na+Na+Na+ADPATPK+K+K+Na+Na+3.Changeinshaperesultsandcausescarriertorelease3Na+outsidethecell.2.ATPissplit,andphosphategroupattachestocarrier.4.Carrierhasashapethatallowsittotakeup2K+.5.Phosphategroupisreleasedfromcarrier.1.Carrierhasashapethatallowsittotakeup3Na+.Sodium-PotassiumPumpDiffusionFacilitatedDiffusionOsmosisInsidethecellCytoplasmPassiveNoenergyActiveEnergyINSUMMARYATPD.ExocytosisandEndocytosis:

TrafficofLargeMoleculesMechanismsthatinvolvefusionwiththeplasmamembraneanduseofvesicles.

Exocytosis(ExoExit)Secretessubstancesoutsideofthecell.

EndocytosisTakessubstancesinsideofthecell.ExocytosisEndocytosisInphagocytosis(“cellulareating”),acellengulfsaparticleandpackagesitwithinafoodvacuole.Inpinocytosis(“cellulardrinking”),acell“gulps”dropletsoffluidbyformingtinyvesicles.Differentendocytosis:Receptor-mediatedendocytosisistriggeredbythebindingofexternalmoleculestomembraneproteins.Copyright?TheMcGraw-HillCompanies,Inc.Permissionrequiredforreproductionordisplay.parameciumsolutesolutea.Phagocytosisb.Pinocytosisvacuolecoatedvesicleplasmamembranecoatedpitc.Receptor-mediatedendocytosis399.9μmvesiclevacuoleformingpseudopodofamoeba0.5μmvesiclesformingcoatedvesiclecoatedpitreceptorproteina(right):?EricGrave/Phototake;b(right):?DonW.Fawcett/PhotoResearchers,Inc.;c(both):CourtesyMarkBretscherTheRoleofMembranesinCellSignalingCellularc