Final answer:
Antiporters in biology are transporters that move two substances in opposite directions. An example is the sodium-hydrogen ion antiporter, which uses the energy from sodium ions to move hydrogen ions out of the cell.
Step-by-step explanation:
In biology, antiporters are transporters that move two different substances in opposite directions. These transporters are a type of secondary active transport system. For example, the sodium-hydrogen ion antiporter uses the energy from the inward flood of sodium ions to move hydrogen ions (H+) out of the cell, helping maintain the cell's pH.