Cephalosporins are what type of antibiotics?

• A. Beta-lactam antibiotics
• B. Macrolides
• C. Tetracyclines
• D. Aminoglycosides

Answer: (A)

Cephalosporins are beta-lactam antibiotics because they share a beta-lactam ring in their chemical structure and work by the same basic mechanism: inhibiting bacterial cell wall synthesis through binding to penicillin-binding proteins, which prevents cross-linking of the peptidoglycan layer. This structural feature and mechanism distinguish them from other antibiotic classes. For context, macrolides inhibit protein synthesis by binding the 50S ribosomal subunit; tetracyclines disrupt protein synthesis by blocking the 30S ribosomal subunit and preventing tRNA attachment; aminoglycosides also target the 30S unit but cause misreading of mRNA and are typically bactericidal. The defining beta-lactam ring and mechanism place cephalosporins in the beta-lactam family.