Which antibiotic prevents protein synthesis by blocking tRNA attachment to the ribosome?

Tetracyclines are a class of antibiotics that work by inhibiting protein synthesis in bacteria. They specifically act on the ribosome by preventing the attachment of transfer RNA (tRNA) to the ribosomal site during translation. This action effectively blocks the incorporation of amino acids into the growing polypeptide chain, thereby disrupting protein synthesis which is essential for bacterial growth and reproduction.

This mechanism of action is fundamental to the effectiveness of tetracyclines in treating various bacterial infections. By interfering with the ribosome's ability to translate mRNA into proteins, tetracyclines effectively starve the bacteria of the proteins they need to survive and multiply.

In contrast, amoxicillin and penicillin are beta-lactam antibiotics that work primarily by inhibiting bacterial cell wall synthesis rather than affecting protein synthesis functions. Erythromycin, on the other hand, also inhibits protein synthesis, but it does so by binding to a different site on the ribosome, preventing the translocation steps necessary for the movement of tRNA from one site to another, rather than blocking the initial attachment of tRNA. This distinguishes tetracyclines in their specific mechanism of action among the options provided.