Which process breaks down triglycerides into glycerol and fatty acids?

Which process breaks down triglycerides into glycerol and fatty acids?

• A. Glycogenolysis
• B. Glycolysis
• C. Gluconeogenesis
• D. Lipolysis

Answer: (D)

Lipolysis is the breakdown of triglycerides into glycerol and free fatty acids. In fat tissue, triglycerides are hydrolyzed by lipases—activated by hormones such as epinephrine and glucagon and inhibited by insulin—releasing glycerol and fatty acids into the bloodstream. Glycerol can be used by the liver in gluconeogenesis or glycolysis, while fatty acids are transported to other tissues to undergo beta-oxidation and form acetyl-CoA for the citric acid cycle, a key energy source during prolonged exercise. The other processes do not break down triglycerides: glycogenolysis breaks down glycogen to glucose, glycolysis breaks down glucose to pyruvate, and gluconeogenesis makes glucose from non-carbohydrate substrates.

Lipolysis is the breakdown of triglycerides into glycerol and free fatty acids. In fat tissue, triglycerides are hydrolyzed by lipases—activated by hormones such as epinephrine and glucagon and inhibited by insulin—releasing glycerol and fatty acids into the bloodstream. Glycerol can be used by the liver in gluconeogenesis or glycolysis, while fatty acids are transported to other tissues to undergo beta-oxidation and form acetyl-CoA for the citric acid cycle, a key energy source during prolonged exercise. The other processes do not break down triglycerides: glycogenolysis breaks down glycogen to glucose, glycolysis breaks down glucose to pyruvate, and gluconeogenesis makes glucose from non-carbohydrate substrates.