Question

which type of mutation always produces a stop codon?
missense
nonsense
silent
point

Explanation:

A nonsense mutation occurs when a change in a single nucleotide (a point mutation) results in the formation of a premature stop codon. This stop codon prematurely terminates protein synthesis. A missense mutation changes a codon to code for a different amino acid. A silent mutation changes a codon but the resulting amino acid is the same (due to the degeneracy of the genetic code). A point mutation is a general term for a single - nucleotide change and can be missense, nonsense, or silent.

Answer:

B. nonsense