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: Biochemistry
[{'content': 'A 55 year old male patient complains of abnormal growth on right cheek. Patient has a habit of tobacco chewing since 30 years. Radiologic findings reveal 8x8cm fungating mass, invading maxilla and mandible on right side. Patient was advised palliative chemotherapy with cisplastin. All of the following changes in DNA are caused by this drug EXCEPT- \nSelect and explain. \nA. A-tracts are replaced by other base, B. Collapse of the helix into the minor groove of A-tract, C. Produce bent structure in DNA, D. The changed structure cannot take up proteins', 'role': 'user'}, {'content': 'Answer: D \nExplanation: In\xa0general, adenine base containing DNA tracts are rigid and straight. Bent conformation of DNA occurs when A-tracts are replaced by other bases or a collapse of the helix into the minor groove of A-tract. Bending in DNA structure has also\xa0been\xa0reported\xa0due\xa0to\xa0photochemical damage or mispairing of bases. Certain\xa0 antitumor\xa0 drugs\xa0 (e.g.\xa0cisplatin) produce bent structure in\xa0 DNA.\xa0Such changed structure can take up\xa0proteins that damage the DNA.\nSatyanarayana- Biochemistry, 3rd edition, pg-77', 'role': 'assistant'}]