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: Microbiology
[{'content': 'Continuous cell culture of bacteria \nSelect and explain. \nA. U tube, B. Craige tube, C. Chemostat device, D. Agar dilution method', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ans. is 'c' i.e., Chemostat device Bacterial cultures can be maintained in a state of exponentional growth over long periods of time using a system of continuous culture. Continuous culture, in a device called chemostat, can be used to maintain a bacterial population at a constant density, a situation that is, in many ways, more similar to bacterial growth in natural environments. In a chemostat microbial cells are grown at a steady state where cell biomass production, substrates and products concentrations remains constant, and growth occurs at a constant rate. These features make a chemostat unique and powerful tool for biological and physiological research.", 'role': 'assistant'}]