At the other end of the fatty acid chain is a carboxyl group which is the functional group that is used to attach the fatty acid chains to the glycerol subunit through a dehydration synthesis reaction. When fatty acids are attached to each of the 3 carbons in the glycerol a triacylglycerol or triglyceride molecule is formed. If a phosphate group attaches to the first carbon in the glycerol, a phosphoglyceride molecule is formed which is an important component of cell membranes. If the carbons in the fatty acid tail has no double bonds between its carbons the fatty acid is said to be saturated. If there is one or more double bonds in the in the fatty acid chains then it is a unsaturated fatty acid.
Saturated fats are usually solid fats at room temperature, while unsaturated fats tend to be oils.
Fats are made from Glycerol and fatty acids. Fatty acids are hydrocarbon chains with a carboxyl group at the end. Triacylglycerides are made when the 3 fatty acids are attached to the 3 hydroxides groups on glycerol. They may be cleaved from the glycerides by a hydrolysis usually do to action of alkalis or bases. The most common base is sodium hydroxides or potassium hydroxide.