Final answer:
Peptidyl transferase, a ribozyme within the large ribosomal subunit, catalyzes the formation of peptide bonds during the elongation phase of protein synthesis.
Step-by-step explanation:
In step 2 of elongation during protein synthesis, the catalysis of peptide bond formation is performed by peptidyl transferase. This enzyme is a ribozyme component integrated into the large subunit of the ribosome, specifically the 50S ribosomal subunit in prokaryotes. The peptidyl transferase catalyzes the bond formation between the amino group of the incoming amino acid attached to the A-site tRNA and the carboxyl group of the amino acid attached to the P-site tRNA, effectively extending the polypeptide chain in a process known as a condensation reaction.