FacilitateciIliffusionandActiveTransportFacilitatedDiffusionMovementofspecificmoleculesacrosscellmembranesthroughproteinchannelsIEachproteinchannelonlyallowsaparticularsubstancestocrossTheproteinfacilitates(helps)thediffusionacrossthemembraneOccurswiththefollowing:1.Chargedmolecules(ions)2.WhenmoleculesaretoolargeAlthoughfacilitateddiffusionisfastandspecific,itisstilldiffusion.HNetmovementofmoleculesacrossamembraneoccursfromthesidewithahigherconcentrationlowerconcentrationside.Doesnotrequireenergy.AftiveTransoortActiveTransportenergy-requiringprocessthatmovesmaterialacrossacellmembraneagainstaconcentrationdifferencei9=energyusedinactivetransportActiveTransportMovematerialsintheoppositedirectionagainstaconcentrationdifferenceRequires:1energy+HIGH+2.transportproteinsExamplesfActiveTransport1. Endocytosis2. ExocytosisMolecularTransport(useofproteinsorproteinchannels)EndocHosisProcessbywhichacelltakesmaterialintothecellbyinfoldingsorpocketsofthecellmembrane.HBTransports:Largermolecules2.SolidclumpsofmaterialenergyPhagocytosis-“cellPhagocytosis一whenextensionsofthecytoplasmsurroundparticles,packageitwithinafoodvacuole,thencellengulfsitiTheprocessofengulfingtakesaLOTofScanningelectronmicrographofaphagocyte(yellow,right)phagocytosinganthraxbacilli(orange,left)PinocytoslsucelldrinkingJustlikeendocytosis;processwherecellstakeupliquidfromthesurroundingVesicleenvironment,fusewithmembrane，andreleasethesefluidfilledvacuoleswithinthecell.ExocytosisExocytosisl-Processbywhichacellreleaseslargeamountsofmaterial.VacuolefuseswithcellmembraneTransports:Largermolecules2.SolidclumpsofmaterialMolecularTransportNa/KPump(Sodium/PotassiumPump)CellscontainhighamountsofKinsidethecellandhighamountsofNaoutsidethecelland，inordertomaintaincellvolumeandrestingcellpotential,thispumpgetsused.highered.mcgraw-hill/sites/0072495855/student_view0/chapter2/animation_how_the_sodium_potassium_pump_works.html