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: Unknown
[{'content': 'The chloride shift occurs rapidly and is essentially complete in \nSelect and explain. \nA. 1 second, B. 2 second, C. 5 second, D. 60 second', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Chloride Shift\nSince the rise in the HCO3– content of red cells is much greater than that in plasma as the blood passes through the capillaries, about 70% of the HCO3– formed in the red cells enters the plasma.\nThe excess HCO3–\xa0leaves the red cells in exchange for Cl–\xa0, a process mediated by Band 3, a major membrane protein.\nThis exchange is called the chloride shift.\nBecause of it, the Cl–\xa0content of the red cells in venous blood is therefore significantly greater than in arterial blood.\nThe chloride shift occurs rapidly and is essentially complete in 1 second.', 'role': 'assistant'}]