The molecules made up of glycerol and fatty acids are lipids, specifically triglycerides.

Here's a breakdown:

* Glycerol: A three-carbon molecule with three hydroxyl (-OH) groups.

* Fatty Acids: Long chains of hydrocarbons (carbon and hydrogen atoms) with a carboxyl group (-COOH) at one end.

* Triglyceride: A molecule formed by attaching three fatty acid molecules to the three hydroxyl groups of glycerol. This process is called esterification.

Triglycerides are the most common type of lipid in the human body and serve as a major source of energy. They are also important for insulation and protection of organs.