Answer:
Proteins are the molecules that are responsible for the movement of molecules.
Step-by-step explanation:
Cell membrane is a barrier around each cell that provides them a shape and also control the movement of molecules coming in or out. This movement of molecules is called membrane transport. The call membrane is composed of phopholipids bilayer and proteins are embedded in this bilayer. These proteins function as receptors for specific molecules or ions and transfer them inside or outside of cell.