Answer. Lipids are macromolecules made up of fatty acids. Lipids include oils and fats. Oils and fats are esters of long chain carboxylic (fatty) acids with glycerol. These esters are made of three fatty acids therefore, they are called triglycerides. General formula of triglycerides is as under.
O
H2C-O-C-R
O
HC-O-C-R
O
H2C-O-C-R