The peptidyl site, or P site, is the location on the ribosome where the growing polypeptide chain is held during protein synthesis.
This is where each new tRNA molecule carrying an amino acid attaches to the ribosome during protein synthesis.
Exit Site (E site): This is where discharged tRNAs leave the ribosome after they have delivered their amino acid.
A long chain of amino acids linked by peptide bonds that forms part of a protein's structure.