This module introduces expected frequencies in the context of understanding amino acid composition. It is intended for an introductory biology audience.
This activity maps to the OpenStax biology textbook, 15.1. The Genetic Code
Student Introduction: Genetic information contained in mRNA is in the form of codons, sequences of three nucleotides, which are translated into amino acids which then combine to form proteins. At certain sites in a protein's structure, amino acid composition is not critical. Yet certain amino acids occur at such sites up to six times more often than other amino acids. In the 1960's, molecular biologists sought to determine if amino acid composition was a reflection of the genetic code or if certain amino acids were naturally selected as optimal.