Radiation damages living tissue mainly because it
- A. heats the tissue significantly
- B. ionises molecules, including DNA, producing reactive fragments
- C. makes the tissue radioactive
- D. changes the pH of the cells
Explanation
Ionisation breaks chemical bonds and generates free radicals that go on to damage DNA, which may kill the cell or, if it is repaired imperfectly, cause a mutation and later a cancer. The energy deposited is far too small to matter as heat. Exposure to gamma or X rays does not make the patient radioactive, which is a common public misconception.