This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: General anatomy, Subject name: Anatomy
[{'content': 'Inhibitor of Apoptosis is \nSelect and explain. \nA. P53, B. Ras, C. Myc, D. Bcl_2', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Ref Robbins 9/e p55; Robbins 7/e p29 Conversely, if cells are exposed to growth factors and other survival signals, they synthesize anti-apoptotic members of the Bcl-2 family, the two main ones of which are Bcl-2 itself and Bcl-xL. These proteins antagonize Bax and Bak, and thus limit the escape of the mitochondrial pro-apoptotic proteins. Cells deprived of growth factors not only activate the pro-apoptotic Bax and Bak but also show reduced levels of Bcl-2 and Bcl-xL, thus fuher tilting the balance toward death. The mitochondrial pathway seems to be the pathway that is responsible for apoptosis in most situa- tions, as we discuss later.', 'role': 'assistant'}]