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: Pathology
[{'content': 'Free radical injury includes all except \nSelect and explain. \nA. Damaged cell membranes, B. Loss of enzymatic activity, C. Single strand break of DNA, D. Vacuolar degeneration', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Cell Injury Caused by Reactive Oxygen Species:\nROS\xa0 causes\xa0 cell\xa0 injury\xa0 by\xa0 damaging\xa0 multiple\xa0 components of cells:\n\nLipid peroxidation of membranes.\xa0\nCrosslinking and other changes in proteins resulting in enhanced degradation or loss of enzymatic activity.\nDNA damage.\nIn\xa0all\xa0these\xa0cases,\xa0cell\xa0death\xa0may\xa0be\xa0by\xa0necrosis, apoptosis, or the mixed pattern of necroptosis.\n\nThe two main morphologic correlates of reversible cell injury are cellular swelling and fatty change.\nMicroscopic examination may show small, clear vacuoles within the cytoplasm; these represent distended and pinched-off segments of the endoplasmic reticulum (ER). This pattern of nonlethal injury is sometimes called hydropic change or vacuolar degeneration.', 'role': 'assistant'}]