<prompt> Which of the following functionally competent of largest unit of the ribosomes?tRNAmRNACatalyze formation of the peptidesFormation of the polyribosomes  <response>: Ribosomes catalyze peptide bond formation between aminoacyl- tRNA aa-tRNA4 bound to the A site of the ribosome and peptidyl- tRNA at the P site.The active site for peptide bond formation, the peptidyl transferase center, is located on the large 50 S ribosomal subunit. High-resolution crystal structures of the 50 S subunit have revealed that the peptidyl transferase center is composed of RNA 23 S rRNA, with no protein within 15 A of the active site 1, 2.This implies that peptide bond formation is catalyzed by RNA and, thus, the ribosome is a ribozyme. 