Causes of mutationSpec 3.37B
Mutations happen naturally and at random, but the incidence (how often they happen) can be increased by exposure to certain things called mutagens.
- Ionising radiation, for example gamma rays, X-rays and ultraviolet (UV) rays.
- Some chemical mutagens, for example chemicals in tobacco.
Exposure to a mutagen makes a mutation more likely. It does not mean that a mutation will definitely happen. This is one reason why people are protected from unnecessary exposure to radiation, and why tobacco smoke is harmful.
Exam tip:
Learn one radiation example and one chemical example: for instance X-rays and chemicals in tobacco. Say they increase the rate of mutation.