Topic overview

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The bacterial 70S ribosome is formed from a 30S subunit, which binds mRNA and decodes codon–anticodon interactions, and a 50S subunit, which catalyzes peptide-bond formation. These subunits assemble during protein synthesis and separate when translation ends; multiple ribosomes can translate one mRNA as a polysome. In bacteria, translation can occur alongside transcription. Several antibiotic groups act on either subunit, while mechanisms such as ribosomal RNA methylation, drug modification, and ribosomal protection can reduce antibiotic activity. The lesson also links ribosomal RNA to bacterial identification and considers how similarities between bacterial and mitochondrial ribosomes relate to some antibiotic toxicities.