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: Physiology
[{'content': 'Rapid diffusion of water across cell membranes depends on the presence of water channels, called aquaporins. Proximal convoluted tubule have: \nSelect and explain. \nA. Aquaporin 1, B. Aquaporin 2, C. Aquaporin 5, D. Aquaporin 9', 'role': 'user'}, {'content': "Answer: A \nExplanation: Aquaporin-1 is localized to both the basolateral and apical membrane of the proximal tubules and its presence allows water to move rapidly out of the tubule along the osmotic gradients set up by active transpo of solutes, and isotonicity is maintained. Ref: Barrett K.E., Barman S.M., Boitano S., Brooks H.L. (2012). Chapter 37. Renal Function & Micturition. In K.E. Barrett, S.M. Barman, S. Boitano, H.L. Brooks (Eds), Ganong's Review of Medical Physiology, 24e.", 'role': 'assistant'}]