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Genetic code

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Revision as of 06:28, 1 December 2013 by Osiris (talk | changes)
A series of codons in part of a messenger RNA (mRNA) molecule. Each codon consists of three nucleotides. This usually represents a single amino acid. The nucleotides are shown by the letters A, U, G and C. This is mRNA, which uses U (uracil). DNA uses T (thymine) instead.

The genetic code is the set of rules by which information encoded within genetic material (DNA or mRNA sequences) is translated into proteins by living cells. Biological decoding is done by the ribosome. This links amino acids together in an order specified by mRNA. It uses transfer RNA (tRNA) molecules to carry amino acids and to read the mRNA. The molecules read the mRNA three nucleotides at a time. These nucleotide triplets are called codons. A codon specifies which amino acid will be added next during protein synthesis. There are some exceptions,[1] but usually a three-nucleotide codon represents a single amino acid.

The genetic code among all organisms is very similar. It can be expressed in a simple table with 64 entries.[2]

References

  1. Turanov AA, Lobanov AV, Fomenko DE, Morrison HG, Sogin ML, Klobutcher LA, Hatfield DL, Gladyshev VN (2009). "Genetic code supports targeted insertion of two amino acids by one codon". Science. 323 (5911): 259–61. doi:10.1126/science.1164748. PMC 3088105. PMID 19131629. {{cite journal}}: Unknown parameter |month= ignored (help)CS1 maint: multiple names: authors list (link)
  2. Nakamoto T (2009). "Evolution and the universality of the mechanism of initiation of protein synthesis". Gene. 432 (1–2): 1–6. doi:10.1016/j.gene.2008.11.001. PMID 19056476. {{cite journal}}: Unknown parameter |month= ignored (help)

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