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': 'Hydroxyproline and hydroxylysine occur principally in \nSelect and explain. \nA. Collagen, B. Elastin, C. Synovium, D. Hyaline', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Hydroxyproline and hydroxylysine occur principally in collagen. Since there is no tRNA for either hydroxylated amino acid, neither dietary hydroxyproline nor dietary hydroxylysine is incorporated during protein synthesis. Ref: Harper&;s biochemistry; 30th edition; Chapter 27 Biosynthesis of the Nutritionally Nonessential Amino Acids', 'role': 'assistant'}]