Which site on the ribosome holds the tRNA that is linked to the polypeptide?

The site on the ribosome that holds the tRNA linked to the polypeptide chain is referred to as the P-site, or the peptidyl site. During translation, the P-site is where the tRNA carrying the growing polypeptide chain is positioned. This allows for the addition of new amino acids to the polypeptide as the ribosome moves along the mRNA.

In the context of protein synthesis, the P-site plays a crucial role in maintaining the existing polypeptide chain while the A-site (aminoacyl site) is responsible for holding the incoming tRNA that brings the next amino acid. The E-site (exit site) is where tRNA, having transferred its amino acid to the growing chain, exits the ribosome after its role in translation is complete. The R-site is not a standard designation in ribosome structure and function, which further supports the correctness of identifying the P-site as the location holding the tRNA linked to the polypeptide.