1.10.4.3. Lipids (Fats, Oils, and Waxes) are another Component of Living Organisms:

• Lipids are third group of organic compounds present in cell of all living organisms. Lipids contain C, H, and O, and that's it. No other elements in lipid molecules are present.
• Carbohydrates always have twice as many hydrogen atoms as oxygen atoms (H:O ratio = 2:1). Lipids never do.  Also, the structural formulas of carbohydrates have the ring while lipids do not.
• Lipids are energy rich compounds.

• A fatty acid is nothing more than a long C-H chain with a carboxyl group (COOH) on the end.
• The carboxyl group gives a molecule an acidic property. Both of the organic acids fatty Acids and amino Acids have carboxyl groups.
• Glycerol is classified as an alcohol (due to the OH's). It always looks the same: Three C's with Three -OH's and everything else H's.

• Combining three fatty acids with one glycerol by the process of DEHYDRATION SYNTHESIS give fatty acids.

• There is no Nitrogen anywhere, so this is definitely not a proteiN reaction.
• Also there are no ring-shaped molecules, so one is not dealing with carbohydrates.
• The hydrolysis (digestion) of a lipid is similar in living organism as is the case of Carbohydrate/proteins and can be summarized as below:

Lipid + Water → 3 Fatty Acids + 1 Glycerol