Acetyl-CoA and NADPH are pre-resquisites for fatty acid synthesis. Acetyl-CoA is produced in the mitochondria by the oxidation of pyruvate and fatty acids and degradation of carbon skeletons of amino acids and from ketone bodies. Mitochondrion is not permeable to acetyl-CoA, so Acetyl-CoA condenses with oxaloacetate in mitochondria to form citrate. Citrate lyase liberates Acetyl-CoA and oxaloacetate. Oxaloacetate in the cytosol is converted to malate.