Which of the following criteria does not pertain to facilitated...

Facilitated transport is a form of passive transport in which materials are moved across the plasma membrane by a transport protein down. Their concentration gradient. It requires integral membrane proteins and highly selective biological membranes to cross. Saturation occurs in facilitated, diffusion because not enough carriers may be available to handle all the free solute molecules. The rate of movement may reach a maximum. Uphill transport is a process in which diffusion of a component occur's from a less concentrated stream to a more concentrated permeable stream.