Cell membrane function

The plasma or cell membrane encloses the cell by forming a barrier between the cytoplasm inside the cell and the extracellular environment. Specialized transport proteins in the membrane allow molecules to cross the membrane. This makes the cell membrane a selective barrier that allows specific molecules to enter or leave the cell. Other proteins form anchors for the cytoskeleton, which gives the cell structure or serve as receptors that allow the cell to interact with its environment.