Where are free fatty acids converted to ketone bodies?

• A. Brain
• B. Adipose tissue
• C. Liver
• D. Muscle

Answer: (C)

Ketogenesis occurs in the liver. During fasting, free fatty acids are released from adipose tissue and travel to the liver, where they are oxidized to acetyl-CoA. When carbohydrate availability is low, oxaloacetate is limited, shunting acetyl-CoA into ketone body synthesis. Enzymes in hepatocytes convert acetyl-CoA into ketone bodies (acetoacetate and beta-hydroxybutyrate, with acetone as a byproduct), which are released into the bloodstream for use by other tissues. The brain and other tissues use ketone bodies but do not produce them in significant amounts.