Answer:
They affect the structure of proteins.
Explanation:
A mutation is any change that occurs to the nucleotide sequence of a gene. A Gene is a segment of the genetic material (DNA) that encodes the protein needed for the growth and development of an organism. Hence, a change in the nucleotide sequence of a gene (mutation) will alter the structure of that protein that the gene encodes.
A protein function is attributed to its structure, hence, once the structure is altered because of unrepaired gene mutations bad, the protein loses functionality. This is why unrepaired gene mutations are bad.
