Plasma Memebrane

The plasma membrane (cell membrane) is made of two layers of phospholipids. The membrane has many proteins embedded in it.

The plasma membrane regulates what enters and leaves the cell. Many molecules cross the cell membrane by diffusion and osmosis.

The plasma membrane will allow certain substances to cross it but not others! Such a membrane is referred to as "selective permeable" (or "semipermeable"). The plasma membrane's permeability depends on a large part on its makeup.

 The outer membrane of cell that controls cellular traffic

• Contains proteins (left, gray) that span through the membrane and allow passage of materials
• Proteins are surrounded by a phospholipid bi-layer.