Which of the following is incorrectly matched? ion channel proteins ; allow the diffusion of charged ions against their electrochemical gradient gated channel proteins ; only open or close in response to specific stimulus such as a voltage change or binding by a signal molecule . channel proteins such as aquaporin; allow passage (down the concentration gradient) of molecules that have a specific size or biochemical characteristics, carrier proteins such as GLUT-1; allow the movement of specific molecules across the membrane down their concentration gradient