Question

ATP hydrolysis directly powers the movement of ?

A. Na+ out of cells.
B. Na+ into cells.
C. K+ out of cells.
D. Cl- into cells.
E. Ca2+ into cells."

Answer 1

ATP hydrolysis using one ATP molecule, which releases 7.3 kcal/mol of energy, can power the movement of about three sodium ions across the cell membrane through the sodium-potassium pump.

Step-by-step explanation:

ATP hydrolysis directly powers the movement of sodium and potassium ions across the cell membrane, particularly through the actions of the sodium-potassium pump. This pump uses the energy from the hydrolysis of one ATP molecule to move three sodium ions (Na+) out of the cell and two potassium ions (K+) into the cell.

Since the hydrolysis of one ATP molecule releases 7.3 kcal/mol, and it takes 2.1 kcal/mol of energy to move one Na+ ion across the membrane, one ATP molecule could theoretically move about three Na+ ions (7.3 kcal/mol divided by 2.1 kcal/mol per Na+ ion equals approximately 3.5).