Question

What happens when a ligand binds to a ligand-gated Na+ channel? There is no net flow of sodium ions. Sodium ions are pumped from low concentration to high concentration. Sodium ions flow passively from low concentration to high concentration. Sodium ions flow passively from high concentration to low concentration.

Answer 1

Sodium ions flow passively from high concentration to low concentration.

Step-by-step explanation:

When a ligand binds to a ligand gated, there's always a flow of ions, in this case we talk about sodium. When the bind is produced, the channel undergoes a conformational change that determines its opening. Remember that the channel, is a protein. In this example we don't talk about a bomb, that's why we suppose that sodium ions are not pumped. As the flow is in favor of gradient, ions always go from high concentration to low.

We say that ions flow PASSIVELY because Ionic channels are sort of passive transport, we don't need ATP.