Start Codon

Definition

The start codon is a specific sequence of three nucleotides in mRNA that signals the start of translation and codes for methionine in eukaryotes or formylmethionine in prokaryotes.

Related terms

Codon:

A sequence of three nucleotides which together form a unit of genetic code in DNA or RNA molecule.

Translation:

The process where genetic information coded in messenger RNA directs the formation of a specific protein at a ribosome in cytoplasm.

Methionine: An essential amino acid that often acts as a starter amino acid in protein synthesis because it corresponds with the 'start' codon on mRNA.