Final answer:
During translation, the A-site holds the next amino acid to be added to the growing polypeptide chain, and this is where incoming charged tRNAs bind.
Step-by-step explanation:
During translation, the site that holds the next amino acid to be incorporated into the polypeptide is the A-site. This site is responsible for binding incoming charged tRNAs that carry amino acids. As the ribosome progresses along the mRNA, peptide bonds form between the amino group of the amino acid attached to the A-site tRNA and the carboxyl group of the amino acid attached to the P-site tRNA. The ribosome then moves, or translocates, and tRNA that was in the A-site moves to the P-site, and the one that was in the P-site moves to the E-site, where it will exit the ribosome.