Peptidyl transferase: the ribosome as a ribozyme
Peptide bond formation on the ribosome is catalyzed by:
Answer A: explanation for every choice
A
Correct. The peptidyl transferase activity resides in the large subunit's rRNA, making the ribosome a ribozyme.
B
Aminoacyl-tRNA synthetases attach amino acids to their tRNAs before translation.
C
The small subunit decodes the mRNA. It does not form peptide bonds.
D
Elongation factors use GTP to deliver tRNAs and move the ribosome.
TakeawayThe ribosome is a ribozyme: rRNA forms the peptide bond.
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Reviewed 2026-11-05 by a medical student. Spot an error? Report it with question ID bb44.