The central dogma
Genetic information flows from DNA to RNA to protein. DNA is copied when a cell divides (replication), a gene is copied into messenger RNA (transcription), non-coding introns are cut out (splicing), and ribosomes read the mRNA three bases at a time to build a protein (translation), which then folds into its working shape.
Four letters, two rules
DNA uses A, T, G and C; RNA swaps T for U. A pairs with T (or U) through two hydrogen bonds, G with C through three. The two strands run in opposite directions, 5′→3′ and 3′→5′, and new strands always grow 5′→3′.
The genetic code
Each three-base codon names one amino acid. Translation starts at AUG (methionine) and ends at UAA, UAG or UGA. Read the wheel from the center out — first, second, third base — to find the amino acid on the rim.
Scoring
Each chapter is worth up to 1,000 points — accuracy counts most, speed adds a bonus. The clock only runs while you have work to do, so take your time reading. In the folding chapter, points depend on how many hydrophobic contacts you make compared with the best possible fold.
What's simplified
The proteins are real human peptide hormones, and the code, pairing rules, splice signals and TATA box are accurate. Shortened for play: the intron is a few dozen bases instead of thousands, the promoter has one clear signal, you build only part of each strand by hand, and folding is shown on a flat square grid. In cells these peptides are cut from longer precursors, and replication and transcription involve many more proteins.
