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
[{'content': 'The enzyme ^9 desaturase catalyzes the conversion of stearic acid into? \nSelect and explain. \nA. Linolenic acid, B. Linoleic acid, C. Oleic acid, D. All of the above', 'role': 'user'}, {'content': "Answer: C \nExplanation: The enzyme ^9 desaturase, in endoplasmic reticulum, catalyzes conversion of stearic acid to oleic acid, which is a MUFA. ^9 desaturase is a mixed-function oxidase, requiring NADPH and O2. Humans cannot introduce double bonds beyond ^9 position (between C10 and terminal methyl group). Hence, linoleic (D9,12 ) and linolenic acid (D 9,12,15) are considered essential fatty acids. Reference: Harper's Illustrated Biochemistry 30th Edition Pg 239", 'role': 'assistant'}]