Rewrite per discussion at http://forum.exercism.org/t/tweak-language-and-formatting-in-protein-translation-description-md/17005/72

Author: codingthat

exercises/protein-translation/description.md

@@ -1,44 +1,29 @@
 # 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
+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:
 
-Codons: `"AUG", "UUU", "UCU"`
-=> which become a protein with the following sequence =>
+|Codon|Amino Acid|
+| --- | --- |
+|AUG|Methionine|
+|UUU, UUC|Phenylalanine|
+|UUA, UUG|Leucine|
+|UCU, UCC, UCA, UCG|Serine|
+|UAU, UAC|Tyrosine|
+|UGU, UGC|Cysteine|
+|UGG|Tryptophan|
+|UAA, UAG, UGA|STOP|
 
-Protein: `"Methionine", "Phenylalanine", "Serine"`
+For example, the RNA string “AUGUUUUCU” has three codons: “AUG”, “UUU” and “UCU”. These map to Methionine, Phenylalanine, and 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.
+### “STOP” Codons
 
-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.
+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.
 
-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.
-
-| Codon              | Amino Acid    |
-| :----------------- | :------------ |
-| AUG                | Methionine    |
-| UUU, UUC           | Phenylalanine |
-| UUA, UUG           | Leucine       |
-| UCU, UCC, UCA, UCG | Serine        |
-| UAU, UAC           | Tyrosine      |
-| UGU, UGC           | Cysteine      |
-| UGG                | Tryptophan    |
-| UAA, UAG, UGA      | STOP          |
+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].