What happens when one of the three codons of UAG, UAA, or UGA reach the A site on a ribosome that is helping facilitate translation?

In eukaryotes, translation of mRNA into a polypeptide is performed by what type of ribosome if the polypeptide is to be secreted from the cell?

Which of the following mutations is a single nucleotide base pair change that results in a codon for a different amino acid?