Final answer:
During peptide chain elongation in protein synthesis, three G-protein family members known as elongation factors (EF-Tu, EF-Ts, and EF-G) are required, which are GTP-hydrolyzing enzymes that facilitate the sequential addition of amino acids to the growing polypeptide chain.
Step-by-step explanation:
Peptide chain elongation in the process of translation requires the involvement of multiple G-protein family members. These GTP-hydrolyzing enzymes, known as elongation factors, play essential roles in facilitating the addition of amino acids to the growing polypeptide chain. Specifically, the elongation factors mentioned are EF-Tu, EF-Ts, and EF-G, which associate with GTP to carry out their roles during protein synthesis. During elongation, EF-Tu, in its GTP-bound form, brings the aminoacyl-tRNA to the ribosome's A site. After the formation of a peptide bond, EF-G, also bound to GTP, assists in translocating the tRNA and mRNA down the ribosome to prepare for the next amino acid addition.