Video Transcript
Consider the following sequence of
mRNA: five prime UAC GAG AAC CGA three prime. Use the codon wheel provided to
determine the sequence of amino acids that this mRNA sequence will be translated
into. (A) Stop, aspartic acid, lysine,
proline. (B) Serine, glycine, glutamine,
serine. (C) Tyrosine, glutamic acid,
asparagine, arginine. (D) Histidine, glutamic acid,
threonine, arginine. (E) Tyrosine, aspartic acid,
glutamine, proline.
In order for a gene in DNA to be
converted into a protein, it needs to go through two steps. First, the DNA sequence is
converted into mRNA during a process called transcription. Then, the nucleotide sequence in
mRNA is converted into a sequence of amino acids in a polypeptide, which can then
fold into a protein.
Let’s look at how a sequence of
mRNA can be translated into amino acids. Here’s a segment of mRNA that is
made up of six nucleotides. A group of three nucleotides in
mRNA is called a codon. In this six-nucleotide sequence of
mRNA, there’s two codons. The specific sequence in a codon
corresponds to a specific amino acid. The sequence ACA corresponds to the
amino acid threonine.
In the codon wheel shown here, we
can work out the corresponding amino acid from the nucleotide sequence of a
codon. For the codon GUC, we start from
the center and work our way out. We can see that this corresponds to
the amino acid valine.
Now let’s write out the sequence of
mRNA given in this question and determine the amino acid sequence. The codon UAC corresponds to the
amino acid tyrosine. The codon GAG corresponds to
glutamic acid. The codon AAC corresponds to
asparagine. And finally the codon CGA
corresponds to arginine.
So now we can see that the correct
answer choice is (C) tyrosine, glutamic acid, asparagine, arginine.
