🧬 Codon Run: Decode the Genetic Code
Your cells read genes three letters at a time. Be the ribosome: read each codon and build the protein!
How to play
- An mRNA is a string of four bases: U C A G. Every group of three is a codon.
- Tap the amino acid the glowing codon codes for (or press 1–4). Every gene starts with AUG and ends with a STOP codon.
- Right answers in a row build a 🔥 streak worth up to +100 per codon. Stuck? Open the 📖 Codon Table (no streak bonus while it's open).
- After each gene, one base mutates. Is it silent (same amino acid), missense (a different one) or nonsense (an early stop)?
- Every gene spells out a real peptide, from oxytocin to a yeast mating signal. Find out which one when you finish it!
About the genetic code
DNA's instructions are copied into messenger RNA (mRNA), which a ribosome reads three bases at a time. Each three-base codon stands for one of 20 amino acids or for "stop". With four bases there are 64 codons: 61 code for amino acids and 3 (UAA, UAG, UGA) end the protein. Because 61 codons share 20 amino acids, most amino acids have more than one codon. Leucine, serine and arginine have six each, while methionine (AUG, also the start signal) and tryptophan (UGG) have just one. Codon Run picks a different synonymous codon each time you play, so you learn that redundancy as you go.
A point mutation changes one base. If the new codon still means the same amino acid it is silent; if it means a different amino acid it is missense (sickle-cell disease is caused by one such change in hemoglobin); if it becomes a stop codon it is nonsense, and the protein is cut short.
The genes in Codon Run are teaching "minigenes": a start codon, the codons for a real peptide and a stop codon. In living cells these peptides (oxytocin, vasopressin, the enkephalins, Substance P and others) are cut from longer precursor proteins and then trimmed and chemically finished. The code itself is the standard genetic code used by almost all life; mitochondria and a few microbes use small variations.
Made the chain? See how chains fold into shapes in FoldLab: Protein Folding.