<prompt> Unsaturated fatty acids are synthesized in thePlasma membraneEndoplasmic reticulumCytosolGolgi complex  <response>: Most of the activity of these enzymes in the biosynthesis of triacylglycerols resides in the endoplasmic reticulum, but some are found in mitochondria.Ref: Harper;s Biochemistry; 30th edition; Chapter 24; Metabolism of Acylglycerols Sphingolipids 