A
symporter is an
integral membrane protein that is involved in the transport of many differing types of molecules across the cell. The symporter works in the
plasma membrane and molecules are transported across the cell membrane at the same time, and is, therefore, a type of
cotransporter. The transporter is called a symporter, because the molecules will travel in the same direction in relation to each other. This is in contrast to the antiport transporter. Typically, the ion(s) will move down the electrochemical gradient, allowing the other molecule(s) to move against the concentration gradient. The movement of the ion(s) across the membrane is
facilitated diffusion, and is coupled with the
active transport of the molecule(s).