Final answer:
Sugars are not transported with sodium ions by the sodium-potassium pump. Sodium ions are extruded from the cell, and potassium ions are imported by an active transport process using ATP. Sugars like glucose are transported by a different mechanism known as a sodium-glucose symporter, a type of secondary active transport.
Step-by-step explanation:
In the sodium-potassium pump, which is an active transport mechanism, sugars are not transported together with sodium ions. Rather, the pump specifically moves sodium ions (Na+) out of the cell, and potassium ions (K+) into the cell. This process is powered by the hydrolysis of ATP (adenosine triphosphate) and occurs in several steps:
- Three sodium ions within the cell bind to the pump.
- ATP is hydrolyzed, which leads to the release of energy and the phosphorylation of the pump.
- The pump changes shape, releasing the three sodium ions outside of the cell.
- Two potassium ions outside the cell bind to the pump.
- The pump reverts to its original shape, moving the potassium ions into the cell.
- The cycle then repeats itself to maintain proper ion concentrations inside and outside the cell.
To transport glucose, a different mechanism known as a symporter is used. The sodium-glucose symporter typically uses the flow of sodium ions into the cell to 'pull' glucose into the cell against its concentration gradient, a process that is made possible by the lower sodium concentrations inside the cell as a consequence of the sodium-potassium pump's activity. This is an example of secondary active transport.