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': 'Following grows in the cell free medium except -a) Rickettsiab) M lepraec) Bartonellad) Syphilis \nSelect and explain. \nA. acd, B. abd, C. abc, D. ab', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Obligate intracellular organisms \n\nTo grow in a medium which does not contain cells (cell free medium), organism should be capable of ATP synthesis.\n\n\nObligate intracellular organisms are not capable of the metabolic pathways for ATP synthesis.\nSo, these organisms are dependent on the ATP of host cells.\nAs they require host cell ATP, they can not grow in the media which do not contain cells (cell free media).\n\n\nSuch organisms are -\n\n\nRickettsiae\nChlamydiae\n\xa0Viruses\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\xa0\nM.leprae\nPathogenic treponemes (syphillis)', 'role': 'assistant'}]