Two essential roles of ribosome during translation are:

• Ribosomes are sites where synthesis of proteins occurs from individual amino acids. It consists of two subunits - larger subunit serves as an amino acid binding site whereas smaller subunit attaches to the mRNA forming a protein synthesizing complex.
• Since large subunit of ribosome has two different sites to attach to tRNA, it facilitates amino acids to come closer for peptide bond formation. Also, ribosome behaves as a catalyst for the formation of peptide bond.

Example - 23s r-RNA acts as a ribozyme in bacteria