Active Transport

  • Morton H. Friedman


In free diffusion and in facilitated transport, the driving force for the flux of a particular solute depends on only the concentrations or thermodynamic potentials of that species at the two faces of the transport barrier. Such transport processes are referred to as passive, and can have either of two outcomes:
  1. 1.

    If at least one of the phases is not practically infinite in extent and the solute is neither consumed nor synthesized, then the process will “run down” to equilibrium as the passive flux acts to equalize the chemical potentials on each side of the barrier.

  2. 2.

    If the solute is consumed or synthesized on one side of the membrane, then a nonequilibrium steady state can be achieved, such that the flux across the membrane equals the rate of consumption or synthesis.



Active Transport Level Flow Active Transport System Chemical Potential Difference Secondary Transport 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.


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Copyright information

© Springer-Verlag Berlin Heidelberg 1986

Authors and Affiliations

  • Morton H. Friedman
    • 1
  1. 1.Applied Physics Laboratory and School of MedicineThe Johns Hopkins UniversityLaurelUSA

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