The factual basis of the following discussion is a step past the MCAT. The point is to help your general fluency. Read for comprehension. Save memorization for medical school.

Fatty acids are broken down by oxidation at the β-carbon. The process begins on the outer mitochondrial membrane by conversion of the fatty acid and ATP into acyl Coa and AMP by fatty acid synthetase. After a complex transport mechanism into the mitochondrial matrix, the acyl Coa is broken down by a repeating sequence of four reactions : oxidation by FAD (dehydrogenation), hydrolysis, oxidation by NAD+ (conversion of a hydroxyl group into a carbonyl group), then thioloysis at the β-carbon, acyl transfer releasing acetyl CoA and producing a new acyl CoA shortened by two carbon atoms. The pathway from acyl Coa to enol Coa to hydroxyacyl CoA to ketoacyl CoA resembles the pathway in the citric acid cycle of succinate to fumarate to malate to oxaloacetate.