# DNA Damage **Causes of DNA Damage:** - Exogenous Causes: Chemical toxins, ionizing radiation ## Types of Mutations ### Point Mutations | Type | Description | | :-------------------: | :-------------------------------------------------------------------------------------: | | *Missense Mutation* | From one amino acid to a different amino acid | | *Nonsense Mutation* | Change from an amino acid to a termination codon | | *Silent Mutation* | A nucleotide change that does not change the amino acid | | *Frameshift Mutation* | Insertion or deletion of a multiple of 1-2 bases causing a change in the reading frame. | ![[Pasted image 20250228202136.png|325]] ### Secondary Mutations - A reverse/back mutation returns the gene to the original arrangement - A compensatory mutation cancels the effect of another mutation - A **suppressor** mutation reduces or eliminates the effects of another mutation