Which term describes a glycerol molecule and three free fatty acids, serving as the main lipid in the food supply?

The term that describes a glycerol molecule bonded to three free fatty acids is triglycerides. Triglycerides are the main form of fat found in both the food supply and the human body, and they serve as a major source of energy. The structure of triglycerides consists of a glycerol backbone to which three fatty acid chains are attached through ester bonds.

This structure is key as triglycerides can be stored in adipose tissue for energy reserves or transported in the bloodstream to provide energy to cells. They play a crucial role in metabolism and overall health, influencing everything from energy levels to hormone production.

In contrast, while phospholipids are also a type of lipid, they consist of two fatty acids and a phosphate group and are important in cell membrane structure but do not serve as the main dietary lipid. Steroids are a class of lipids that include cholesterol and hormones, characterized by a four-ring carbon structure, and do not fit the description given in the question. Cholesterols refer specifically to cholesterol, which is a type of steroid that is also found in bodily membranes and is a precursor for various hormones but is not comprised of a glycerol and three fatty acids.