diff --git a/exercises/protein-translation/description.md b/exercises/protein-translation/description.md index dc9209269c..4f79794b40 100644 --- a/exercises/protein-translation/description.md +++ b/exercises/protein-translation/description.md @@ -1,36 +1,17 @@ # Description -Translate RNA sequences into proteins. +Your job is to translate RNA sequences into proteins. -RNA can be broken into three-nucleotide sequences called codons, and then translated to a protein like so: +RNA strands are made up of three-nucleotide sequences called **codons**. +Each codon translates to an **amino acid**. +When joined together, those amino acids make a protein. -RNA: `"AUGUUUUCU"` => translates to - -Codons: `"AUG", "UUU", "UCU"` -=> which become a protein with the following sequence => - -Protein: `"Methionine", "Phenylalanine", "Serine"` - -There are 64 codons which in turn correspond to 20 amino acids; however, all of the codon sequences and resulting amino acids are not important in this exercise. -If it works for one codon, the program should work for all of them. -However, feel free to expand the list in the test suite to include them all. - -There are also three terminating codons (also known as 'STOP' codons); if any of these codons are encountered (by the ribosome), all translation ends and the protein is terminated. - -All subsequent codons after are ignored, like this: - -RNA: `"AUGUUUUCUUAAAUG"` => - -Codons: `"AUG", "UUU", "UCU", "UAA", "AUG"` => - -Protein: `"Methionine", "Phenylalanine", "Serine"` - -Note the stop codon `"UAA"` terminates the translation and the final methionine is not translated into the protein sequence. - -Below are the codons and resulting amino acids needed for the exercise. +In the real world, there are 64 codons, which in turn correspond to 20 amino acids. +However, for this exercise, you’ll only use a few of the possible 64. +They are listed below: | Codon | Amino Acid | -| :----------------- | :------------ | +| ------------------ | ------------- | | AUG | Methionine | | UUU, UUC | Phenylalanine | | UUA, UUG | Leucine | @@ -40,6 +21,18 @@ Below are the codons and resulting amino acids needed for the exercise. | UGG | Tryptophan | | UAA, UAG, UGA | STOP | +For example, the RNA string “AUGUUUUCU” has three codons: “AUG”, “UUU” and “UCU”. +These map to Methionine, Phenylalanine, and Serine. + +## “STOP” Codons + +You’ll note from the table above that there are three **“STOP” codons**. +If you encounter any of these codons, ignore the rest of the sequence — the protein is complete. + +For example, “AUGUUUUCUUAAAUG” contains a STOP codon (“UAA”). +Once we reach that point, we stop processing. +We therefore only consider the part before it (i.e. “AUGUUUUCU”), not any further codons after it (i.e. “AUG”). + Learn more about [protein translation on Wikipedia][protein-translation]. [protein-translation]: https://en.wikipedia.org/wiki/Translation_(biology)