Streptomycin and gentamicin primarily act on which ribosomal subunit?

Streptomycin and gentamicin are aminoglycoside antibiotics that specifically target the bacterial ribosome, which is crucial for protein synthesis. These antibiotics bind to the 30S ribosomal subunit of prokaryotic ribosomes. This binding interferes with the translation process by causing misreading of the mRNA, ultimately leading to the production of faulty proteins, which can be detrimental to bacterial survival.

In bacterial ribosomes, the 70S ribosome is composed of a 50S and 30S subunit. While the 50S subunit is also essential for protein synthesis, streptomycin and gentamicin directly affect the 30S subunit by disrupting the fidelity of translation. The 80S ribosome pertains to eukaryotic cells and does not interact with these specific antibiotics, making this option irrelevant in the context of their mechanism of action.