Genetic code: Difference between revisions

Revision as of 10:44, 30 January 2004

Revision as of 10:53, 30 January 2004

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[[de:Genetischer Code]] [[eo:Genetika Kodo]] [[es:Codón]] [[ja:遺伝暗号]] [[nl:Genetische code]] [[pl:Kod genetyczny]]

The '''genetic code''' is a [[mapping]] that [[biological cell]]s use to [[translation (biology)|translate]] sequences of three [[nucleotide]] bases, called '''[[codons''' or '''triplets''']], into [[amino acid]]s. Nearly all living things use the same genetic code, called the '''standard genetic code''', and all use small variations of it. The code is followed repeatedly, creating many amino acids strung together into a [[protein]].

This process is called [[protein biosynthesis]]. First, a sub-sequence of [[DNA]] called a [[gene]] is [[transcription|transcribed]] (rewritten) into [[RNA]]. An RNA is a sequence of repeating nucleotide bases. The bases in RNAs are [[adenine]], [[guanine]], [[cytosine]] and [[uracil]]. The RNA is divided into groups of three bases, called codons. Each codon represents one amino acid. There are 64 codons. For example, the RNA sequence UUUAAACCC contains the codons UUU, AAA and CCC, each of which specifies one amino acid. So, this RNA sequence represents a protein sequence, three amino acids long. ([[DNA]] is also sequence of nucleotide bases, but there [[thymine]] takes the place of uracil.)