Which metabolic pathway primarily uses stored fat reserves (triacylglycerols) to generate ATP in cells?

• A. Fatty acid β-oxidation (followed by the citric acid cycle and oxidative phosphorylation)
• B. Glycolysis
• C. Glycogenesis
• D. Pentose phosphate pathway

Answer: (A)

Verified step by step guidance

1. Identify the main metabolic pathways involved in energy production and storage: Glycolysis, Glycogenesis, Pentose Phosphate Pathway, and Fatty Acid \(\beta\)-oxidation.
2. Understand that triacylglycerols (stored fats) are broken down into glycerol and free fatty acids, which are then processed to generate ATP.
3. Recognize that Glycolysis primarily metabolizes glucose, Glycogenesis is involved in glycogen synthesis, and the Pentose Phosphate Pathway generates NADPH and ribose-5-phosphate, not ATP from fats.
4. Focus on Fatty Acid \(\beta\)-oxidation, which is the pathway that catabolizes fatty acids into acetyl-CoA units, feeding into the citric acid cycle for further ATP production.
5. Conclude that the primary pathway using stored fat reserves to generate ATP is Fatty Acid \(\beta\)-oxidation, followed by the citric acid cycle and oxidative phosphorylation.