This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Amino Acids Basics, Subject name: Biochemistry
[{'content': 'Which amino acid spares the use of methionine - \nSelect and explain. \nA. Cysteine, B. Glycine, C. Histidine, D. Arginine', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. is \'a\' i.e., Cysteine "Adequate dietary source of cysteine \'spares \' methionine".o Methionine is an essential amino acid.o Methionine is required for synthesis of cysteine (thus cysteine is non-essential amino acid)o Thus, cysteine can spare the requirment of methionine in diet.', 'role': 'assistant'}]