Final answer:
The catalytic sites for peptide bond formation during translation are found in the large subunit RNAs of the ribosome. Peptidyl transferase activity is carried out by the rRNA within the large subunit, which acts as a ribozyme.
Step-by-step explanation:
The catalytic sites for peptide bond formation during translation are found in a component of the ribosome known as the peptidyl transferase center, which is an integral part of the large ribosomal subunit. Specifically, the enzymatic activity responsible for catalyzing peptide bond formation is attributed to rRNA within the large subunit, making this rRNA a ribozyme. The actual site of catalysis where amino acids are bonded together is a part of the large subunit's rRNA and not associated with ribosomal proteins. Therefore, the correct answer to the question is A. large subunit RNAs.
Ribosomes consist of two subunits: the large and the small. Each subunit has a distinct role during translation, with the small subunit typically involved in the correct positioning of the mRNA and the large subunit carrying out the catalytic function, including peptide bond formation. The large subunit contains three important sites: the A (aminoacyl) site, the P (peptidyl) site, and the E (exit) site. The P site harbors the tRNA with the growing polypeptide chain, while the A site binds to the incoming charged tRNA. The peptidyl transferase functionality, which is an RNA-based ribozyme integrated into the large subunit, is crucial for the peptide bond formation between amino acids during protein synthesis.