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#potassium

4 public questions tagged with this topic.

Membrane Transportation

Which ion has the highest intracellular concentration in most animal cells?

Ionic composition asymmetry between cytosol and extracellular fluid is actively established but reflects passive equilibrium for some ions. Primary determinant is Na+/K+ ATPase, P-type pump undergoing E1 to E2 transitions phosphorylating Asp369 in DKTGT motif, exporting three sodium and importing two potassium per ATP hydrolyzed. This creates extracellular sodium about 145 millimolar versus intracellular about 12 millimolar, and intracellular potassium about 140 millimolar versus extracellular 4 millimolar. Leak potassium channels dominated at rest maintain membrane potential near minus 90 mil

Ref: Lodish et al., Molecular Cell Biology, Section: Intracellular Ion Composition - Na+/K+ ATPase and K+ Dominance.

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Membrane Transportation

Which ion has the highest intracellular concentration in most animal cells?

Intracellular ion composition is highly asymmetric relative to extracellular fluid actively maintained using ATP to support excitability volume and enzyme function. In most mammalian cells at rest dominant intracellular cation is potassium one thirty to one forty millimolar inside versus four to five outside ten to thirtyfold gradient while sodium inverse ten to fifteen inside versus one forty five outside chloride four to twenty inside versus one ten outside bicarbonate ten inside versus twenty five outside free calcium extremely low one hundred nanomolar inside versus one point two millimola

Ref: Lodish et al., Molecular Cell Biology, 8th ed., Chapter 11: Intracellular Ion Composition – High K+.

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