Which drug is a tetracycline antibiotic?

Which drug is a tetracycline antibiotic?

• A. Doxycycline (Vibramycin)
• B. Penicillin G
• C. Azithromycin
• D. Cephalexin

Answer: (A)

Tetracyclines inhibit bacterial protein synthesis by reversibly binding to the 30S ribosomal subunit, blocking the attachment of aminoacyl-tRNA and preventing peptide chain elongation. Doxycycline is a member of this class, and its four-fused-ring structure is characteristic of tetracyclines, which is why it’s classified as such. The other drugs belong to different antibiotic families: Penicillin G targets cell wall synthesis as a beta-lactam; Azithromycin is a macrolide that binds the 50S ribosomal subunit to inhibit translocation; Cephalexin is a cephalosporin, also a beta-lactam that disrupts cell wall synthesis. Thus, doxycycline is the tetracycline antibiotic.

Tetracyclines inhibit bacterial protein synthesis by reversibly binding to the 30S ribosomal subunit, blocking the attachment of aminoacyl-tRNA and preventing peptide chain elongation. Doxycycline is a member of this class, and its four-fused-ring structure is characteristic of tetracyclines, which is why it’s classified as such. The other drugs belong to different antibiotic families: Penicillin G targets cell wall synthesis as a beta-lactam; Azithromycin is a macrolide that binds the 50S ribosomal subunit to inhibit translocation; Cephalexin is a cephalosporin, also a beta-lactam that disrupts cell wall synthesis. Thus, doxycycline is the tetracycline antibiotic.