Final answer:
Uniporters can indeed transport molecules in the opposite direction if the concentration gradient is reversed, as they carry molecules passively along the concentration gradient.
Step-by-step explanation:
The statement is accurate. Uniporters are membrane transport proteins that facilitate the movement of a single type of molecule or ion across the cell membrane. The direction of movement for a uniporter is determined by the concentration gradient of the transported substance.
In the context of uniporters running "backwards," it refers to the reversal of the normal direction of transport based on the concentration gradient. Uniporters, like other passive transporters, move substances from an area of higher concentration to an area of lower concentration. However, if the concentration gradient is reversed, meaning the higher concentration is inside the cell, the uniporter can facilitate the movement of the molecule or ion in the opposite direction—toward the lower concentration outside the cell. This process occurs without the need for energy input and is driven solely by the concentration differential.