Passive transport
Molecules are always moving randomly. A concentration difference produces net diffusion even though individual molecules move in both directions. At equilibrium, molecular exchange continues but there is no net concentration-driven movement. Facilitated diffusion uses specific channels or carriers; it does not by itself push a solute uphill. For ions, both concentration and electrical forces contribute to the electrochemical gradient. A carrier-mediated transport rate can level off when the available carriers are occupied. Adding more transport proteins can increase capacity, while increasing a gradient can increase net transport only within the system’s physical limits.
Glucose can move into a cell through a passive carrier when its concentration is higher outside than inside. If the concentrations become equal and no other process maintains a gradient, exchange can continue without sustained net inward flow.
Equilibrium does not mean molecules stop moving. Also, the presence of a protein does not mean transport is active.