BioCoach Activity

Concept 5: The Genetic Code: RNA vs. Protein

The language of RNA to the language of protein: The genetic code is a triplet code in which three nucleotides in RNA specify one amino acid in protein.

RNA consists of four "letters": A, U, G, and C.

Protein consists of 20 "letters": the amino acids.

How can RNA code for protein?

  • If 1 RNA base codes 1 amino acid, RNA could code for only 4 amino acids. Not enough coding capacity for all 20 amino acids.
  • If 2 RNA bases code for 1 amino acid, RNA could code for 42 = 16 amino acids. Still not enough coding capacity for 20 amino acids.
  • If 3 RNA bases code for 1 amino acid, RNA could code for 43 = 64 amino acids. More than enough coding capacity for 20 amino acids.

To see each of the following properties of the genetic code highlighted in the figure, push the relevant button.