. Electrolytes in biological systems, incorporating papers presented at a symposium at the Marine Biological Laboratory in Woods Hole, Massachusetts, on September 8, 1954 . 10 20 30 40 50 60 Fig. 7. Effect of Mg^^ on the removal of K^ from the medium by actively metaboHzing yeast cells. 4 0 K-. « CONTROL V VSr*^.- â⢠35 PH "V ^^ â 1 _^__L,CI *\ ^-4 t: ^--â¢.iif^l 30 ^^^^ âº-^ -â¢^KCl ^ -,,_ 25 - TIME IN MINUTES 1 ' 1 Lâ Fig. 8. Changes in the pH of the medium during fermentation of glucose, as influenced by various ions. the presence of Mg"*"^ proceeds at a rate which
. Electrolytes in biological systems, incorporating papers presented at a symposium at the Marine Biological Laboratory in Woods Hole, Massachusetts, on September 8, 1954 . 10 20 30 40 50 60 Fig. 7. Effect of Mg^^ on the removal of K^ from the medium by actively metaboHzing yeast cells. 4 0 K-. « CONTROL V VSr*^.- â⢠35 PH "V ^^ â 1 _^__L,CI *\ ^-4 t: ^--â¢.iif^l 30 ^^^^ âº-^ -â¢^KCl ^ -,,_ 25 - TIME IN MINUTES 1 ' 1 Lâ Fig. 8. Changes in the pH of the medium during fermentation of glucose, as influenced by various ions. the presence of Mg"*"^ proceeds at a rate which is only a little slower than that in its absence, despite the fact that the concentration of Mn++ is sufficiently high to displace virtually all of the K+ from the cell surface (fig. 7). Thus it must be concluded that the K+ binding sites which have been discussed previ- ously (page 72), play no essential role in K+-transport. Any interaction between K+ and the transport system must occur in a location inaccessible to bivalent cations, either deeper within the cytoplasm, or perhaps within the lipid phase of the membrane. OTHER MONOVALENT CATIONS Other monovalent cations can be transported into the cell in exchange for H+ by the same mechanism that transports K+. A simple method for demon-
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Keywords: ., bookcentury1900, booksubjectelectrolytes, booksubjectphysiologyc
