Read for comprehension. Fatty acid synthesis from acetyl coenzyme A is accomplished by the complex of enzymes fatty acid synthase. Important reaction types in the process include acyl transfer, the reverse of the decarboxylization pathway of malonic acid and related compounds, and reaction at the α carbon (aldol condensation). Being enzyme catalyzed, the mechanisms vary from the model reactions.

The basic process begins with carboxylation of acetyl CoA producing malonyl CoA. The addition of carbon dioxide to create the reactive α carbon which can then combine with another acetyl carrier protein group, producing an acetoacetyl acyl carrier protein. The successive reactions occur with intermediates bound to Acyl Carrier Protein (ACP). Condensation of Acetyl-ACP (or other Acyl ACP) and Malonyl-ACP yields acetoacetyl-ACP, and release of CO2. Further processing occurs with reduction of the ketone carbonyl to hydroxyl followed by dehydration to alkene followed by reduction by NADPH to an aliphatic sequence.

Chain extension to 6, 8, 10 carbon atoms continues with additional reactions of the sequence with a malonyl group bound to the acyl carrier protein. Glycolysis and decarboxylization of pyruvate followed by fatty acid synthesis represents a major portion of the biosynthetic pathway from carbohydrate (glucose) to triglycerides and phospholipids. The biosynthesis of terpenes is related in the similar buildup of the fundamental isoprene unit.