CP-2156 Life In The Universe

Figure 1. The function of transfer RNA (tRNA) in the synthesis of a protein molecule is to make a chain of amino acids that reflects the nucleotide sequence of the template represented by messenger RNA (mRNA).

Figure 1. The function of transfer RNA (tRNA) in the synthesis of a protein molecule is to make a chain of amino acids that reflects the nucleotide sequence of the template represented by messenger RNA (mRNA). The aminoacyl-tRNA synthetase first joins a specific RNA molecule to its corresponding amino acid with a covalent bond. In the diagram, amino acids are represented by squares, hexagons, etc. The tRNA with the amino acid attached to it binds at the A site to the ribosome. This interaction requires specific hydrogen bonding between the three codon bases on the mRNA strand that specify the amino acid and the three anticodon bases of the tRNA. From the tRNA molecule in the adjacent P site there is transferred the growing polypeptide chain to the tRNA in the A site The "empty" tRNA leaves the P site, and the ribosome moves along the mRNA a distance of one codon so that the tRNA carrying the polypeptide chain is shifted from the A site to the P site. Then the cycle can begin anew. It takes about 5 msec for one cycle in procaryotes.

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