Question

Which of the following statements most accurately describes how the [K]i and [K]o affect the EK?

The farther apart [K]i and [K]o are, the farther EK moves from 0 mV.

The closer together [K]i and [K]o are, the farther EK moves from 0 mV.

Answer 1

The correct statement is that the farther apart the intra- and extracellular potassium concentrations are, the farther the equilibrium potential for potassium (EK) moves from 0 mV. This relationship is explained by the Nernst equation.

Step-by-step explanation:

The effect of the intra- and extracellular potassium ion concentrations, denoted as [K]i and [K]o, on the equilibrium potential for potassium, known as EK, adheres to the Nernst equation. The Nernst equation specifies that the equilibrium potential for an ion across a membrane is directly related to the logarithm of the ratio of the ion's concentrations on each side of the membrane. Therefore, the correct statement is: 'The farther apart [K]i and [K]o are, the farther EK moves from 0 mV.' When the concentration gradient for potassium ions across the membrane increases, the equilibrium potential becomes more negative or positive (depending on ion charge direction), moving farther from 0 mV.