Dna codes for assembly of amino acids / forms a polypeptide chain (proteins - enzymes) Each triplet codes for one amino acid. Single amino acid may have up to 6 different triplets for it due to the redundancy of the code / some amino acids are coded by more than one codon (degenerate code) Same triplet code will give the same amino acid in all organisms (universal code) We have 64 possible combinations of the 4 bases in triplets, 43. No base of one triplet contributes to part of the code next to it (non-overlapping) Few triplets code for start and stop sequences for polypeptide chain formation: start: aug, stop: uaa, uag, uga. Alleles: different forms of the same gene. Gene: length of dna that carries the code for a protein (enzyme: enzyme effect the cell"s metabolism, visible changes are described with the phenotype, the phenotype is influenced by the metabolic pathway.