Describe how one amino acid is added to a polypeptide that is being formed at a ribosome during translation - AQA - A-Level Biology - Question 3 - 2021 - Paper 1

The addition of an amino acid to a polypeptide during translation occurs in a series of coordinated steps: First, the transfer RNA (tRNA) molecule, which carries a specific amino acid, interacts with the ribosome. The tRNA recognizes the corresponding codon on the messenger RNA (mRNA) that is being translated at the ribosome. This interaction is facilitated by the base pairing between the tRNA's anticodon and the mRNA's codon. Once the correct tRNA is bound to the ribosome, a condensation reaction takes place, whereby the carboxyl group of the amino acid in the tRNA forms a peptide bond with the amino group of another amino acid in the growing polypeptide chain. This process requires energy, typically provided by ATP, to ensure the peptide bond is formed correctly, leading to the elongation of the polypeptide.