Question

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

(a) Na+ and A- (negatively charged proteins)
(b) K+ and Cl-
(c) Na+ and Cl-
(d) K+ and A- (negatively charged proteins)

Answer 1

The highest concentrations of sodium (Na+) and chloride (Cl-) ions are found outside of the cell due to the activity of the sodium-potassium pump, which maintains these ion gradients.

Step-by-step explanation:

The concentrations of sodium (Na+) and chloride (Cl-) ions are highest outside of the cell. This is because sodium ions are actively pumped out of the cell, while potassium (K+) ions are pumped into the cell by the sodium-potassium pump, which uses ATP to maintain these concentration gradients. Consequently, the extracellular fluid (ECF) has higher concentrations of Na+ and Cl-, whereas the intracellular fluid (ICF) has a higher concentration of K+ ions. Negatively charged proteins mainly remain inside the cell (intracellular), balancing the positive charge of K+ ions.