Final answer:
During protein synthesis, two GTP molecules are hydrolyzed for each amino acid added to the growing peptide chain.
Step-by-step explanation:
The process of protein synthesis involves the hydrolysis of GTP (guanosine triphosphate) to provide the necessary energy for the ribosome to catalyze the addition of amino acids to the growing peptide chain. In the elongation cycle of protein synthesis, two GTP molecules are hydrolyzed for each amino acid that is incorporated into the peptide chain. One GTP is used during the binding of the aminoacyl-tRNA to the A site of the ribosome, and another GTP is hydrolyzed to move the ribosome along the mRNA during the translocation step.