Illustration of a cell membrane in fish eye perspective. The cell membrane is a complex part of the cell which controls the movement of substances in and out of the cell. It is a phospholipid bilayer that is selectively permeable to ions and organic molecules. Ion channels are required to allow and control the transport of these molecules across the membrane. Channel proteins can be seen in this illustration, including a chloride channel (yellow) and acetate permease (ActP). Several different types of membrane receptors are also visible including: opioid receptors; LDL receptors; and acetyl choline receptors. Glycolipids on the surface are depicted in turquoise.