This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of protein and amino acid, Subject name: Biochemistry
[{'content': 'which of the following is a essential amino acid ? \nSelect and explain. \nA. Lysine, B. Alanine, C. Asparagine, D. Glycine', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Essential amino acids are tryptophan valine threonine leucine lysine phenylalanine &methionine-total 8amino acids (TV TILL 8 PM). their carbon skeleton cannot be synthesized by human beings &so preformed amino acid are to be taken in food for normal growth. Normal growth will not occur if one such amino acid is deficient in the diet. Ref: DM Vasudevan - Textbook of Biochemistry for Medical Students, 7th edition, page no: 27', 'role': 'assistant'}]