The mRNA formed from the repeating tetranucleotide UUAC incorporates only three amino acids, but the use of UAUC incorporates four amino acids. Why?

Video transcript

Hi everyone. Let's take a look at this practice problem together. How many amino acids will be incorporated by an M. RNA with the following nucleotide sequence. And here's our sequence. M. RNA strand. Now we're basically as how many amino acids will be produced from this M. RNA strand for M R. N. A. For translation occur. Remember that every three nucleotides equals a code on and one coat on produces one amino acid and translation begins at a stop start code on. And that start code on is always a U. G. Now translation ends at a stop code on. And there are three options for the stop code on it can be either you A you A G or U. G. A. So let's take a look at our sequence. I'm gonna enlarge it a bit and let's identify our start code on which is a U. G. So a U. G. Is at the very beginning. So this is our first coat on. So that's the start code on. Next we have a G. G. As our next code on. So this would be code on to followed by U. U. U. Is the next code on code on three. And we end with U G. A. And U G. A. Is a stop code on. Now recall that the stop code on does not produce an amino acid. It literally terminates translation at that point. So we have 123 code ons. Therefore we would produce three amino acids. So a three is the correct answer. Alright everyone I hope you found this helpful. And I'll see you soon for the next practice problem.