Which antibiotic does NOT interfere with protein synthesis?

• A. Aminoglycosides
• B. Cephalosporins
• C. Tetracyclines
• D. Lincomycin

Answer: (B)

Antibiotics work on different bacterial targets, and this question focuses on whether a drug blocks protein synthesis. Cephalosporins act by inhibiting cell wall synthesis: they block penicillin-binding proteins involved in cross-linking peptidoglycan, which weakens the cell wall and leads to bacterial lysis. They do not interact with ribosomes or translation, so protein synthesis isn’t affected.

In contrast, the other drugs disrupt protein production by targeting the ribosome: aminoglycosides bind the 30S subunit and cause misreading of mRNA, tetracyclines bind the 30S to prevent tRNA binding, and lincomycin binds the 50S subunit to block peptidyl transferase.