Cell membranes are represented according to a fluid-mosaic model, due to the fact that they are:

• Fluid – the phospholipid bilayer is viscous and individual phospholipids can move position
  

• Mosaic – the phospholipid bilayer is embedded with proteins, resulting in a mosaic of components
  

When drawing the fluid-mosaic model, it is important to correctly represent the following:

• Phospholipids should be arranged in a bilayer, with the polar and non-polar regions identified

• Glycoproteins and glycolipids should be facing the extracellular side of the membrane
  

• Integral proteins should be embedded within the bilayer, while peripheral proteins should be anchored to one side
  

• Cholesterol may be included in animal cell membranes (it will be interspersed between the fatty acid tails)
  

Fluid-Mosaic Model