Potassium Channel ion rate and Gradient

AI Thread Summary
The discussion centers on the function of potassium channels, which filter potassium ions at a rate of 100 million ions per second. It highlights the significant difference in potassium ion concentration between the cell's interior (100 mM) and the exterior (5 mM), leading to a much higher ratio of water molecules to potassium ions inside (553:1) compared to outside (11,060:1). The inquiry focuses on how this rapid ion flow affects local concentrations of potassium ions around the channel, specifically within a few nanometers of its opening. The implications of these concentration changes on cellular function and ion dynamics are central to understanding the role of potassium channels in cellular physiology.
somasimple
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Hi All,
A potassium channel is designed to filter out potassium ions at a maximum rate of 100,000,000 ions s-1
A common concentration (cell's interior) of potassium is 100 mM and 5 mM outside.
This means there is 553 water molecules for 1 potassium ion inside (55.3/0.100) and 11,060 water molecules for a ion outside (55.3/0.005).
https://www.physicsforums.com/showthread.php?t=247778

If the channel acts as a sieve then what happen to the local concentrations, inside and outside?

ref:
rate =>
http://www.pdb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb38_1.html
water =>
http://www.pdb.org/pdb/static.do?p=education_discussion/molecule_of_the_month/pdb38_4.html

ps: local concentration (concentration that exists just around the channel ~ few nm)
 
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