Using energy from ATP, sodium-potassium pumpsactively transport ions in both directions across the membrane. 2. Some potassium channelsare open, allowing certain ions to move out of the cell through them. 3. The sodium channels are closed, preventing certain ions from entering the cell through them. 4. The concentration of sodium ionsis higher outside the cell than inside. 5. The concentration of potassium ionsis higher inside the cell than outside.