<prompt> ratelimiting enzyme in fatty acid synthesis ?malonyl co a synthaseacyl co synthasemalonyl co a reductasecholestrol acyl transferase  <response>: Fatty Acid Synthesis Fatty acids are built from 2-C units derived from acetyl-CoA Acetate units are activated for transfer to growing FA chain by conversion to malonyl-CoA Decarboxylation of malonyl-CoA and reducing power of NADPH drive chain growth Chain grows to 16-carbons eight acetyl-CoAs Other enzymes add double bonds and more ref : lipincott 9th ed 