Final answer:
Lipolysis is the hydrolytic breakdown of triglycerides into glycerol and free fatty acids, mainly in adipose tissue, triggered when the body requires energy from fats instead of carbohydrates. Glycerol can enter the glycolysis pathway or be used in gluconeogenesis, while fatty acids are oxidized for energy production.
Step-by-step explanation:
Lipolysis and its Role in Energy Metabolism
Lipolysis is the process of breaking down lipids, specifically triglycerides, into glycerol and free fatty acids (FFAs). This breakdown occurs mainly in the adipose tissue by the action of an enzyme called hormone-sensitive lipase, which is regulated by various hormones. When energy from carbohydrates is inadequate, lipolysis is initiated, and the FFAs are transported to various tissues to undergo ß-oxidation, producing acetyl CoA that enters the Krebs cycle. Meanwhile, glycerol is transported to the liver and kidneys, where it can contribute to gluconeogenesis or enter the glycolysis pathway as dihydroxyacetone phosphate (DHAP).
Fatty acid catabolism involves a process called ß-oxidation, where FFAs are broken down, resulting in the production of acetyl CoA, which is a vital component for the Krebs cycle. Subsequently, the fatty acids provide a dense source of energy as they yield significantly more energy upon oxidation compared to carbohydrates or proteins, making them essential during periods of low glucose availability.