The genetic code

The genetic code is the set of rules by which information encoded in genetic material (DNA or RNA sequences) is translated into proteins (amino acid sequences) by living cells. Specifically, the code defines a mapping between tri-nucleotide sequences called codons and amino acids; every triplet of nucleotides in a nucleic acid sequence specifies a single amino acid.
Each protein-coding in the DNA is transcribed into a template molecule, known as messenger RNA or mRNA. This in turn is translated on the ribosome into an amino acid chain or polypeptide. The process of translation requires transfer RNAs specific for individual amino acids with the amino acids covalently attached to them. Some transfer RNAs do not have an amino acid counterpart. When a codon for such a transfer RNA is read, the translation stops.
Almost all living creatures use the same genetic code. The table below is based on the standard version. (U stands for Uracil in RNA; in DNA this would be a T for Thymine).

**Codon table:** This table gives the 64 (4³) possible triplets
A=Adenine, C=Cytosine, G=Guanine and U=Uracil
		U	C	A	G
		2^e base
1^e base	U	UUU Phenylalanine UUC Phenylalanine UUA Leucine UUG Leucine	UCU Serine UCC Serine UCA Serine UCG Serine	UAU Tyrosine UAC Tyrosine UAA Stop UAG Stop	UGU Cysteine UGC Cysteine UGA Stop UGG Tryptophan
	C	CUU Leucine CUC Leucine CUA Leucine CUG Leucine	CCU Proline CCC Proline CCA Proline CCG Proline	CAU Histidine CAC Histidine CAA Glutamine CAG Glutamine	CGU Arginine CGC Arginine CGA Arginine CGG Arginine
	A	AUU Isoleucine AUC Isoleucine AUA Isoleucine AUG Methionine¹	ACU Threonine ACC Threonine ACA Threonine ACG Threonine	AAU Asparagine AAC Asparagine AAA Lysine AAG Lysine	AGU Serine AGC Serine AGA Arginine AGG Arginine
	G	GUU Valine GUC Valine GUA Valine GUG Valine	GCU Alanine GCC Alanine GCA Alanine GCG Alanine	GAU Aspartate GAC Aspartate GAA Glutamate GAG Glutamate	GGU Glycine GGC Glycine GGA Glycine GGG Glycine

¹ The AUG codon codes for methionine and serves as a starting point. The first AUG in mRNA marks the starting point for translation.