Structure of cell membranes

• keep cellular components in cell
• control what goes in and out
• isolating organelles from cytoplasm, allowing cellular processes to occur alone
• site for biochemical reactions
• allows cells to change shape
• when phospholipids are exposed to water, they form a bilayer or micelle
• integral (transmembrane) proteins span the whole width of the membrane
• peripheral proteins are confined to the inner or outer surface of membrane
• glycoproteins are proteins with an attached carbohydrate chain(s)
• cholesterol ($C_{27}H_{46}O$) - controls membrane fluidity - more cholesterol = less fluid = less permeable - keeps membranes stable at normal body temperatures, so without it, cells would burst open