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': 'Urea cycle occurs in which of the following body organs? \nSelect and explain. \nA. Liver, B. Gastrointestinal tract, C. Spleen, D. Kidney', 'role': 'user'}, {'content': 'Answer: A \nExplanation: The urea cycle (also known as the ornithine cycle) is a cycle of biochemical reactions occurring in many animals that produces urea from ammonia (NH3). This cycle was the first metabolic cycle discovered (Hans Krebs and Ku Henseleit, 1932), five years before the discovery of the TCA cycle. In mammals, the urea cycle takes place primarily in the liver, and to a lesser extent in the kidney. Ref: Textbook of Biochemistry By DM Vasudevan, 3rd Edition, Page163', 'role': 'assistant'}]