How does the potassium channel maintain selectivity for potassium versus sodium ions?
A) The ion size is the determining factor.
B) The size of the ion and associated waters relative to the pore size are the determining factors in channel selectivity.
C) Dehydration of the potassium ion is compensated energetically by interactions with oxygen atoms in the selectivity filter, which is not possible with sodium ions.
D) Potassium ions associate with six molecules of water while sodium associates with four, thus allowing selectivity.
E) None of the answers is correct.

Question

Quizplus · Accepted Answer

The potassium channel selectivity filter is structured to compensate for the energy required to dehydrate potassium ions by providing optimal interactions with the oxygen atoms lining the filter, which sodium ions cannot achieve due to their smaller size and different hydration energy.

How Does the Potassium Channel Maintain Selectivity for Potassium Versus