Final answer:
The transport receptors that move molecules in the opposite direction are called antiporters. These receptors use the energy from the movement of other molecules to transport substances in the opposite direction across the cell membrane.
Step-by-step explanation:
Transport receptors that move molecules in the opposite direction are called antiporters. Antiporters are secondary active transport systems that use the energy from the movement of other molecules to transport substances in the opposite direction across the cell membrane.
For example, the sodium-hydrogen ion antiporter uses the energy from the inward flow of sodium ions to move hydrogen ions (H+) out of the cell. This is important for maintaining the pH of the cell's interior.
Another example of antiporters is the sodium-glucose symporter, which uses sodium ions to move glucose molecules into the cell against its concentration gradient.