This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of nucleic acids, Subject name: Biochemistry
[{'content': 'All of the following molecules are a pa of the synthesis of a purine ring except? \nSelect and explain. \nA. Lysine, B. Glycine, C. Glutamine, D. Aspaate', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Reference: Harpers illustrated biochemistry 30th edition', 'role': 'assistant'}]