Name a common antibiotic that inhibits cell wall synthesis and a typical example.

• A. Tetracyclines
• B. Beta-lactams (e.g., penicillin)
• C. Macrolides
• D. Fluoroquinolones

Answer: (B)

Antibiotics that target the bacterial cell wall work by blocking the enzymes that cross-link peptidoglycan, which is the mesh-like layer giving the wall its strength. Beta-lactam antibiotics perform this by binding penicillin-binding proteins and inhibiting the transpeptidation step, preventing proper cross-linking. Without a strong cell wall, actively growing bacteria burst from osmotic pressure. A classic example is penicillin, a well-known member of this class. Other drug classes listed work on different targets: one inhibits protein synthesis at the ribosome, another also blocks protein synthesis but at a different subunit, and another interferes with DNA replication.