Transfer RNA
Molecular Biology · Biochemistry
Say it: TRANS-fur ar-en-AY
Transfer RNA is a short adaptor RNA that brings a specific amino acid to the ribosome and pairs with the matching mRNA codon through its anticodon.
Also: tRNA, transfer ribonucleic acid
Definition
What is Transfer RNA?
Transfer RNA (tRNA) is a short RNA molecule, about 70 to 90 nucleotides long, that acts as the adaptor between the genetic code and proteins. Base pairing within the chain folds it into a cloverleaf of four arms, which then folds further into a compact L shape. At one end sits the anticodon, three bases that pair with a matching codon on messenger RNA. At the other end, the 3' end, which finishes in the bases CCA, the tRNA carries its amino acid.
Each tRNA is loaded, or charged, with the correct amino acid by an enzyme called an aminoacyl-tRNA synthetase. There is at least one of these enzymes for each of the 20 amino acids, and the reaction uses energy from ATP. During translation, a charged tRNA enters the ribosome at the A site, where its amino acid is joined to the growing chain; the tRNA then shifts to the P site and finally leaves, empty, from the E site. Cells have roughly 40 to 60 kinds of tRNA, fewer than the 61 codons for amino acids, because some anticodons can pair with more than one codon, a flexibility at the third codon position called wobble.
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Terms that go with it
- TranslationTranslation is the process in which a ribosome reads the codons of a messenger RNA and links amino acids in that order to build a protein.
- CodonA codon is a sequence of three nucleotides in DNA or messenger RNA that stands for one amino acid or tells the ribosome to stop.
- Messenger RNAMessenger RNA is the RNA copy of a gene that carries protein-building instructions from DNA to the ribosomes, where it is read in three-base codons.
- RibosomeA ribosome is a molecular machine of RNA and protein that reads messenger RNA and joins amino acids in the order it specifies to build a protein.
- Amino acidAn amino acid is a small organic molecule with an amino group, a carboxyl group and a side chain; amino acids link together to form proteins.
- RNARNA is a usually single-stranded nucleic acid, built with the sugar ribose and the base uracil, that carries and uses genetic information to make proteins.
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Checked against
Written for biofideX in plain words, after checking these references:
- NHGRI Talking Glossary: Transfer RNA (tRNA)
- OpenStax Biology 2e, 15.5 Ribosomes and Protein Synthesis
- OpenStax Biology 2e, 3.5 Nucleic Acids
- LibreTexts, Cells: Molecules and Mechanisms (Wong), 10.5 tRNA are Rather Odd Ducks
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