Sugars nutrition and

The accumulative pumping of ions or of some metabolites thus appears in frogskin [12], in excitable nerve or muscle membranes, in glucose or other sugar nutritions and in many other cases. A number of more mechanistical models which contain macromolecular or smaller unidentified transporters of the actively transported species have been drawn, but until recently none of these models could be tested or verified in vitro. Many of them are cited in Stein s book [13] or other collective works. 

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