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': 'Carbamoyl group of carbamoyl phosphate is derived from ? \nSelect and explain. \nA. Ammonia, B. Citrulline, C. Ornithine, D. Arginosuccinate', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Ammonia 1st reaction of urea cycle is synthesis of carbamoyl phosphate by condensation of ammonia (NH4') and CO2.The carbamoyl group of carbomoyl phosphate is derived from NH4. and a bicarbonate ion.The reaction is energetically demanding (two ATP) and is catalyzed by carbomoyl phosphate synthase LCPS-I is allosterically activated by N-acetyl glutamate.", 'role': 'assistant'}]