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ID:40351786
大小:6.57 MB
页数:67页
时间:2019-07-31
《Lecture 4-transport-11_195703938》由会员上传分享,免费在线阅读,更多相关内容在学术论文-天天文库。
1、Chapter5TheMovementofSubstancesAcrossCellMembranes1.Principlesofmembranetransport2.Passivetransport3.Activetransport4.Indirectactivetransport•MembraneTransportofSmallMoleculesandtheElectricalPropertiesofMembranesChapter5inthetextbook11.Principlesofmembranetranspo
2、rtA.Theplasmamembraneisaselectivelypermeablebarrier.Itallowsforseparationandexchangeofmaterialsbetweentheinsideandoutsideofthecell.B.Theprotein-freelipidbilayersarehighlyimpermeabletoions.C.Theenergeticsofsolutemovement:a)Diffusionisthespontaneousmovementofmateri
3、alfromaregionofhighconcentrationtoaregionoflowconcentration.b)Thefree-energychangeduringdiffusionofnonelectrolytesdependsontheconcentrationgradient.c)Thefree-energychangeduringdiffusionofelectrolytesdependsontheelectrochemicalgradient.3D.Transportprocesseswithina
4、neukaryoticcell45∑Solutescrossmembranebysimplediffusion∑Ifunchargedsolutesaresmallenough,theycanmovedowntheirconcentrationgradientsdirectlyacrossthelipidbilayerbysimplediffusion.∑Mostsolutescancrossthemembraneonlyifthereisamembranetransportproteintotransferthem.∑
5、Passivetransport,inthesamedirectionasaconcentrationgradient.∑ActivetransportismediatedbycarrierDiffusionofsmallmoleculesacrossproteinsagainstaconcentrationgradientphospholipidbilayersandrequiresaninputofenergy.6Permeabilityofsmallmoleculesthroughsyntheticlipidbil
6、ayers72.PassivetransportA.ComparisonofPassivetransportandActivetransport8B.Twoclassesofmembranetransportproteins∑Carrierproteinsareresponsibleforboththepassiveandtheactivetransport.∑Channelproteinsareonlyresponsibleforpassivetransport.9Thekineticsofsimplediffusio
7、nandcarrier-mediateddiffusion10∑Carrierproteinsbindoneormoresolutemoleculesononesideofthemembraneandthenundergoaconformationalchangethattransferthesolutetotheothersideofthemembrane.11∑Facilitateddiffusion:Protein-mediatedmovement,movementdownthegradientThecarrier
8、protein,theGlucosetransporter(GluT1)intheerythrocytePM,changesconformationtofacilitatethetransportofglucose.12∑Mostofthechannelproteinsareionchannels,including
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