This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Metabolism of carbohydrate, Subject name: Biochemistry
[{'content': 'Hyperammonemia impairs Citric acid cycle by depleting \nSelect and explain. \nA. Pyruvate, B. a-ketoglutarate, C. Oxaloacetate, D. Succinate', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Hyperammonemia, as occurs in advanced liver disease, leads to loss of consciousness, coma, and convulsions as a result of the impaired activity of the citric acid cycle, leading to reduced formation of ATP. Ammonia both depletes citric acid cycle intermediates (by withdrawing a-ketoglutarate for the formation of glutamate and glutamine) and also inhibits the oxidative decarboxylation of a-ketoglutarate. Reference: Harper; 30th edition; Page no: 161', 'role': 'assistant'}]