L07 Chem 481 Lecture Notes - Lecture 39: Serca, Chemotherapy, Transition-Minimized Differential Signaling
13 Dec 2016
School
Department
Course
Professor
Document Summary
7 december 2016: membrane transport, basics of transport, channels vs. transporters, channels are either open or closed. No energy input, only flow down a concentration gradient. Like an enzyme, lowers energy barrier to crossing the membrane. Free diffusion (of small molecules) when pore is open, fast flow, 107 ions per second, usually by a knockdown mechanism. Gating and selectivity control when the channel is open and what goes through. Exact mechanism of opening and closing varies: transporters are only open to one side at a time. Energy is required to move molecules against a concentration gradient. Only n molecules moved per transport cycle, relatively slow (102-105 mlx per second) 2 sources of energy: primary = atp driven, secondary = uses electrochemical gradient. Coupling to an electrochemical gradient created by a primary active transporter (secondary active transporter: the potential energy contained in a gradient is used to drive transport. All gradients must first be created by primary active transporters.
