What type of lipid is made up of three fatty acids attached to a glycerol?

Triglycerides are a type of lipid composed of three fatty acids linked to a glycerol backbone. This structure makes triglycerides the most common form of fat found in the body, serving primarily as an energy storage molecule. When the body requires energy, it can break down triglycerides into their constituent fatty acids and glycerol, which can then be used for energy production.

Understanding the components of triglycerides is essential, as they play critical roles in metabolism and energy balance. The body primarily stores triglycerides in adipose tissue, allowing for a reserve of energy that can be mobilized when needed. This function is vital for maintaining energy homeostasis, especially during periods of fasting or increased physical activity.

Other answer choices relate to different concepts. Nitrogen balance pertains to the state of nitrogen in the body, particularly in relation to protein metabolism. Polyunsaturated fatty acids refer to a type of fatty acid that contains multiple double bonds, important for various physiological functions, but does not describe the structure of triglycerides. Resting energy expenditure (REE) is a measure of energy expenditure at rest and isn't a type of lipid. Understanding triglycerides' structure helps reinforce the role they play in nutrition and energy metabolism.