The right answer is: controls the movement of substances into and out of cells.
This picture represents a plasma membrane.
The plasma membrane is the membrane that delimits a cell. It separates the cytoplasm from the outside environment.
Special proteins ensure the selective permeability of the membrane (pores), the recognition of chemical signals or carry markers (MHC antigens ...).
The pores are the doors of the membrane. They are macromolecular buildings of protein or glycoprotein nature, sometimes very complex. They are inserted in the bilayer and control exchanges between intracellular and extracellular (with receptors, carriers).
