第二章细胞的基本功能2.1细胞膜的物质转运功能几种跨膜物质转运transportacrosscellmembrane方式PassivetransportActivetransportsimplediffusionfacilitateddiffusioncarriermediateddiffusionchannelmediateddiffusionPrimaryactivetransportSecondaryactivetransportNa+-K+pumpH+pumpCa2+Pump•对于不带电荷的分子，影响其跨膜移动的力是concentrationgradient，对于带电的离子，除了concentrationgradient外还有electricalgradient。二者的综合作用称有electrochemicalgradient,orelectrochemicalpotential,产生作用力称electrochemicaldrivingforce。•Amoleculeorionthatcrossesthemembranebymovingdownaconcentrationorelectrochemicalgradientandwithoutexpenditureofmetabolicenergyissaidtobetransporte...
