© 2006 by Zack Smith. All rights reserved.
All genes are composed of sequences of codons, which are triplets of nucleotide bases (A C G T/U). Ribosomes convert these sequences into proteins, which are polymers of amino acids.
Of the 64 possible codons, there are 20 amino acids coded for, 3 stop codons, and 1 start codon (the amino acid methionine). There are many redundant codons, which is important for protecting against transcription errors and mutations.
The Universal Codon of Life
|First Base||Second Base||Third Base|
|U||UUU = phenylalanine||UCU = serine||UAU = tyrosine||UGU = cysteine||U|
|UUC = phenylalanine||UCC = serine||UAC = tyrosine||UGC = cysteine||C|
|UUA = leucine||UCA = serine||UAA = stop||UGA = stop||A|
|UUG = leucine||UCG = serine||UAG = stop||UGG = tryptophan||G|
|C||CUU = leucine||CCU = proline||CAU = histidine||CGU = arginine||U|
|CUC = leucine||CCC = proline||CAC = histidine||CGC = arginine||C|
|CUA = leucine||CCA = proline||CAA = glutamine||CGA = arginine||A|
|CUG = leucine||CCG = proline||CAG = glutamine||CGG = arginine||G|
|A||AUU = isoleucine||ACU = threonine||AAU = asparagine||AGU = serine||U|
|AUC = isoleucine||ACC = threonine||AAC = asparagine||AGC = serine||C|
|AUA = isoleucine||ACA = threonine||AAA = lysine||AGA = arginine||A|
|AUG = methionine||ACG = threonine||AAG = lysine||AGG = arginine||G|
|G||GUU = valine||GCU = alanine||GAU = aspartate||GGU = glycine||U|
|GUC = valine||GCC = alanine||GAC = aspartate||GGC = glycine||C|
|GUA = valine||GCA = alanine||GAA = glutamate||GGA = glycine||A|
|GUG = valine||GCG = alanine||GAG = glutamate||GGG = glycine||G|
Start & Stop codons
There is only one start codon, which is AUG. This is also the methionine amino acid.
There are three stop codons: UAA, UGA, UAG.