Below is shown a partial sequence of a eukaryotic mRNA molecule
that includes the stop
codon. In this sequence, adjacent codons are separated by a blank
space.

… UUU CUG UUG CAG UGU UAG AAC UAU UGA CCG GGU …

1. Using the genetic code determine the sequence of amino
acids coded for by the 3′ end of this open reading frame (ORF).

2. An amber suppressor mutation is a mutation that allows for UAG
to code for an amino
acid and to not act as a stop codon. If the mRNA described above
was expressed
(translated) in a cell with an amber mutation that allowed UAG to
code for tyrosine
(tyr), what would be the sequence of amino acids coded for at the
3′ end of its ORF?

3. Eukaryotic mRNAs frequently have multiple ‘additional’ in-frame
stop codon present
after the first stop codon. What, if any, function would these
additional stop codons
have?

4. Additional stop codon typically differ from the first stop
codon. e.g. if the first stop
codon is UAG, the next will be either UGA or UAA. What is the
functional advantage of
having additional stop codons that differ in sequence from the
first stop codon?