Final answer:
Indirect active transport for glucose and sodium ions occurs via secondary active transport. Sodium ions' movement into the cell, powered by primary active transport, facilitates the uphill transport of glucose through symporters against its concentration gradient.
Step-by-step explanation:
The co-transport of glucose with sodium ions is considered indirect active transport because it depends on the electrochemical gradient established by the primary active transport of sodium and potassium ions.
Sodium-glucose symporters allow glucose to be transported into the cell against its concentration gradient by harnessing the energy from the influx of sodium ions, which move down their own gradient. Sodium ions come into the cell more easily due to the action of the sodium-potassium pump, which functions in primary active transport.
This pump actively exports sodium ions out of the cell and pumps potassium ions in, using ATP as an energy source, creating a high concentration of sodium outside of the cell. The sodium ions then move back into the cell through the symporter, bringing glucose with them, in an act of secondary active transport.