Some types of mutations can cause greater changes in proteins because they result in a different amino acid being translated. This different amino acid provokes a different primary structure, a different active conformation and, in the end, a different biological activity. A certain type of point mutation (when a single base pair is altered), for example, can lead to this when it is a missense mutation. It can also lead to translate to a synonymous codon (coding for the same amino acid), but in this case it does not effect the protein and the mutation is called silent.