Final answer:
Lipolysis is the breakdown of triglycerides into fatty acids and glycerol, followed by β-oxidation of fatty acids into acetyl CoA, which enters the Krebs cycle to generate ATP, especially when glucose is scarce.
Step-by-step explanation:
The process by which triglycerides are broken down into free fatty acids is known as lipolysis. During lipolysis, triglycerides are hydrolyzed into their two principal components, fatty acids and glycerol, in the cytoplasm. The fatty acids then undergo a process called β-oxidation, wherein they are oxidized into acetyl CoA molecules within the mitochondria.
These acetyl CoA molecules subsequently enter the Krebs cycle, also known as the citric acid cycle, which plays a critical role in the production of ATP, the energy currency of the cell.
It is important to note that during periods of low glucose availability, the body relies more heavily on the breakdown of triglycerides into acetyl CoA molecules as an alternative energy source. This process is efficient as fat yields more energy per unit mass compared to carbohydrates and proteins, making it a significant energy reservoir.