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THE MECHANISM OF THE PERMEATION OF CELLS BY NON‐ELECTROLYTES
Author(s) -
Fisher R. B.,
Nimmo I. A.
Publication year - 1972
Publication title -
quarterly journal of experimental physiology and cognate medical sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.925
H-Index - 101
eISSN - 1469-445X
pISSN - 0033-5541
DOI - 10.1113/expphysiol.1972.sp002146
Subject(s) - electrolyte , permeation , diffusion , chemistry , membrane , limiting , biophysics , chemical physics , chemical engineering , thermodynamics , biochemistry , physics , biology , mechanical engineering , electrode , engineering
Theoretical time‐courses of cellular permeation by non‐electrolytes have been derived, given that the rate‐limiting step is ( a ) either the carrier transport or the passive diffusion of the non‐electrolyte across the cell membrane, or ( b ) the uniformly slow diffusion of the non‐electrolyte throughout the protoplasm. It is demonstrated that although in some circumstances the time‐courses of carrier transport and uniformly slow diffusion may be indistinguishable at any one concentration, they can be distinguished by differences in the concentration‐dependence of their parameters: the parameters of whichever hypothesis is valid are independent of concentration. The time‐courses of uptake of D‐glucose, L‐arabinose and D‐xylose by human erythrocytes are shown by this criterion to be consistent only with the hypothesis of carrier transport.