E1: Membrane Potential

Explain how the resting membrane potential is generated.

The resting membrane potential is generated by unequal ion distribution (high Na⁺ outside, high K⁺ inside), selective membrane permeability (primarily K⁺ leak channels), and the Na⁺/K⁺ ATPase maintaining these gradients, resulting in a negative intracellular voltage (~–70 mV).

Explain how chemical and electrical components of driving force influence the movement of substances across cell membranes.

The chemical component drives ions from high to low concentration, while the electrical component drives ions toward opposite charges. Together, they determine the net direction and magnitude of ion movement.

Recall the Nernst Equation and be able to use the equation to explain the flow of ions.

The Nernst Equation calculates an ion’s equilibrium potential based on its concentration gradient. Ions flow in a direction that moves the membrane potential toward their equilibrium potential.

Predict changes in membrane potential caused by alterations in ion concentration gradients or drugs that block ion channel function.

The membrane potential changes toward the equilibrium potential of permeable ions; altering ion gradients or blocking channels shifts Vm depending on which ions can move.