Genetic code

The genetic code is a set of rules defining how the four-letter code of DNA is translated into the 20-letter code of amino acids, which are the building blocks of proteins. The genetic code consists of sequences of three nucleotides that are called “codons” and the correspondence to a given amino acid. Genes are the functional segments of DNA, which allow the production of a functional RNA molecule upon transcription. With four possible bases, we have 4³=64 different codons to encode the 20 different amino acids. Although each codon is specific for only one amino acid (or one translation stop signal), the genetic code is described as redundant because there are examples in which more than one codon can codify a single amino acid. An important thing to note is that the genetic code does not overlap, this means that a single nucleotide cannot be part of two adjacent codons, each nucleotide is part of only one codon. Furthermore, with only rare variations reported, the genetic code is universal. Remarkable exceptions can be found in mitochondria, which have a genetic code with slight variations.

G6 TP4
Lic. Bioquímica