This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
[{'content': 'Common substrate for purine and pyrimidine synthesis are all except ? \nSelect and explain. \nA. Glutamine, B. Glycine, C. Aspaate, D. Carbon dioxide', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Ans. is b i.e., Glycine Glutamine, aspaate (aspaic acid) and CO, are preursors for both purines & pyrimidines.In de novo synthesis, purine ring is formed from variety of precursors is assembled on ribose-5-phosphate.', 'role': 'assistant'}]