Final answer:
The order of amino acids in a polypeptide is determined by the hydrogen bonds between the mRNA codon and the tRNA's anticodon. The tRNA molecule is charged with its specific amino acid by aminoacyl tRNA synthetase, ensuring accurate protein synthesis.
Step-by-step explanation:
The order in which amino acids are added to a polypeptide chain is determined by hydrogen bonding between each codon on the mRNA and the anticodon of the tRNA carrying the amino acid. The anticodon arm of the tRNA contains a sequence of three nucleotide bases that are complementary to the genetic code in mRNA for that particular amino acid. This specific pairing ensures that the amino acids are added in the correct sequence to form a functional protein during the process of translation.
During translation, tRNA molecules with their attached amino acids approach the mRNA strand within the ribosome. The anticodon of a tRNA molecule pairs with the corresponding codon on the mRNA molecule through base-pairing rules, ensuring that the correct amino acid is added to the growing polypeptide chain. This high-fidelity matching is crucial for the proper synthesis of proteins, as the sequence and number of amino acids determine a protein's structure and function.
A tRNA molecule is first 'charged' with its appropriate amino acid by an enzyme called aminoacyl tRNA synthetase. This enzyme recognizes the tRNA's specific structure and the amino acid it is meant to carry, facilitating the correct attachment through an ester bond to the tRNA's aminoacyl arm. Once charged, the tRNA is equipped to participate in protein synthesis at the ribosome.