This animation shows how mutations can arise when DNA is damaged.

DNA can be damaged by radiation and reactive molecules, such as free radicals. As discussed in the animation, this damage may create mutations by chemically changing the DNA. Most mutations are corrected by DNA repair processes in the cell. In rare cases, however, mutations can accumulate and cause genetic diseases such as cancer.

Depending on students’ background, it may be helpful to pause the animation at various points to discuss different structures or molecules.