(tRNA) A type of * RNA molecule that binds to amino acids in the cytoplasm and assists in their incorporation into polypeptide chains at ribosomes. The tRNA molecule is shaped like a clover leaf. Each amino acid binds only to a specific type of tRNA molecule. At one end of a tRNA molecule is a characteristic sequence of three bases, the * anticodon , which will temporarily pair with a complementary triplet, the * codon , in messenger RNA. At the same time the amino acid will detach from its tRNA and form a peptide bond with the amino acid that preceded it. By this means the polypeptide grows by the addition of amino acids one at a time. The amino acid that is incorporated will be determined by the specificity of an amino acid for a particular type of tRNA molecule and the specificity of pairing between the anticodon and codon. See translation. |
