AAMC FL Practice Exam

What are triglycerides composed of?

1. A single glycerol and three fatty acids

2. One glycerol and two fatty acids

3. Three glycerols and one fatty acid

4. Two glycerols and three fatty acids

The correct answer is: A single glycerol and three fatty acids

Triglycerides are a type of lipid that play a crucial role in energy storage and metabolism. They are composed of a single molecule of glycerol and three fatty acids. The glycerol serves as the backbone to which the fatty acids are esterified. This structure is fundamental to the formation of triglycerides, as the fatty acids can vary in their chain length and degree of saturation, influencing the physical properties of the triglyceride, such as whether it is solid or liquid at room temperature. The uniqueness of this structure allows triglycerides to efficiently store large amounts of energy in a compact form, making them a primary source of fuel for the body, especially in adipose tissue. When energy is needed, triglycerides can be broken down through a process called lipolysis, where they are hydrolyzed into glycerol and fatty acids for use in metabolic pathways. Understanding the composition and structure of triglycerides is essential for grasping broader concepts related to biochemistry, nutrition, and metabolism.