During elongation, what type of bond forms between the amino acids on the tRNAs in the A and P sites?

• A. Hydrogen bond
• B. Ionic bond
• C. Disulfide bond
• D. Peptide bond

Answer: (D)

During elongation in translation, the bond that forms between the amino acid on the A-site tRNA and the growing polypeptide attached to the P-site tRNA is a peptide bond. This covalent amide linkage is created by the ribosome’s peptidyl transferase activity, transferring the growing chain from the tRNA in the P site to the amino group of the amino acid on the A-site tRNA. The result is a longer polypeptide attached to the A-site tRNA, with the P-site tRNA now deacylated and ready to move to the E site. Hydrogen bonds, ionic interactions, and disulfide bonds do not create this covalent link between the adjacent amino acids; they may stabilize structures or interactions elsewhere, but the crucial bond that extends the protein is a peptide bond.