This document discusses mutations in DNA and their effects. It defines mutations as changes in the DNA nucleotide sequence. Different nucleotide sequences result in different proteins and physical traits. Mutations can be insertions, deletions, or substitutions of nucleotide bases. These changes can alter the amino acid sequence of proteins and cause frameshift mutations. Point mutations involve a single base change, while missense mutations substitute one amino acid. Nonsense mutations create a stop codon. Silent mutations substitute a base but do not change the amino acid.