How do anticodons in tRNA facilitate translation?

Anticodons in tRNA facilitate translation by pairing with the corresponding codons on mRNA to add specific amino acids to the growing polypeptide chain.

In the process of protein synthesis, the role of transfer RNA (tRNA) is crucial. Each tRNA molecule carries a specific amino acid and an anticodon, a sequence of three nucleotides that is complementary to a codon on the messenger RNA (mRNA). The anticodon is the key element that allows the tRNA to recognise and bind to the correct codon on the mRNA.

During translation, the mRNA molecule is read by the ribosome in a 5' to 3' direction. The ribosome exposes each codon (a sequence of three nucleotides on the mRNA) one at a time. The tRNA molecule with the matching anticodon then binds to this exposed codon through base pairing rules. This ensures that the correct amino acid, carried by the tRNA, is added to the growing polypeptide chain.

For example, if the codon on the mRNA is UAC, the anticodon on the tRNA would be AUG. This tRNA would carry the amino acid methionine, which would then be added to the polypeptide chain. This process continues until a stop codon is reached on the mRNA, signalling the end of translation and the release of the completed protein.

The anticodon-codon pairing is therefore essential for the accuracy of protein synthesis. Any errors in this pairing can lead to the incorporation of the wrong amino acid, potentially altering the structure and function of the protein. This highlights the importance of the anticodon in ensuring the fidelity of translation.

In summary, anticodons in tRNA facilitate translation by ensuring the correct amino acids are added to the polypeptide chain in the correct order, as dictated by the sequence of codons on the mRNA. This is a fundamental process in the synthesis of proteins, which are essential for the structure and function of all living organisms.