Lipid

A lipid is a "water-insoluble biomolecule that is highly soluble in organic solvents" by definition . The lipid's we come across most often are those which play the most important role in forming the lipid bilayer membranes around cells, these are phospholipids. They (like all lipids) contain a hydrophobic, long hydrocarbon chain 'tail', they also contain a 'head'. In phospholipids the main component of this 'head' is a phosphate, it is also formed from an alcohol and a platform bonded to the phosphate creating the hydrophilic part of the lipid. Lipids are amphiphatic, they have both a hydrophilic and a hydrophobic part.