Question

The concentrations of which two ions are highest outside the cell?

A. Sodium and potassium.
B. Potassium and chloride.
C. Calcium and magnesium.
D. Chloride and sodium.

Answer 1

The two ions with the highest concentration outside the cell are sodium (Na+) and chloride (Cl-). Sodium is roughly 10 times more concentrated outside the cell than inside, while potassium (K+) is more concentrated within the cell.

Step-by-step explanation:

The concentrations of ions vary between the inside and outside of cells. The ions with the highest concentration outside the cell are sodium (Na+) and chloride (Cl-). Sodium is the principal ion in the fluid outside of cells, with concentrations about 10 times higher outside than inside. Chloride ions also have a high concentration in the extracellular fluid (ECF). On the other hand, potassium (K+) ions are more concentrated inside the cell. The sodium-potassium pump actively regulates these ion concentrations by pumping sodium and potassium out and using ATP for energy.