This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of lipid, Subject name: Biochemistry
Unsaturated fatty acids are synthesized in the 
Select and explain. 
A. Plasma membrane, B. Endoplasmic reticulum, C. Cytosol, D. Golgi complex
B: Endoplasmic reticulum
Answer: B: Endoplasmic reticulum 
Explanation: 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