Mode of Action

Here’s a flashcard-style set for the mechanisms of action (MOA) or bacterial targets of key antibiotics — a great quick-study tool:


💊 Antibiotic Mechanisms of Action (MOA)


Q: What is the MOA of Tetracycline?
A: Inhibits protein synthesis by binding the 30S ribosomal subunit, blocking tRNA attachment.


Q: What is the MOA of Erythromycin?
A: Inhibits protein synthesis by binding the 50S ribosomal subunit, preventing translocation.


Q: What is the MOA of Penicillin?
A: Inhibits cell wall synthesis by blocking transpeptidase enzymes (cross-linking peptidoglycan).


Q: What is the MOA of Amoxicillin?
A: A type of penicillin; also inhibits cell wall synthesis via transpeptidase inhibition.


Q: What is the MOA of Polymyxin?
A: Disrupts the cell membrane of Gram-negative bacteria by interacting with phospholipids (causes leakage).


Q: What is the MOA of Sulfonamides?
A: Inhibits folic acid synthesis by blocking dihydropteroate synthase (enzyme in folate pathway).


Q: What is the MOA of Trimethoprim?
A: Also blocks folic acid synthesis, but targets dihydrofolate reductase, a downstream enzyme.


Q: What is the MOA of Rifampin?
A: Inhibits RNA synthesis by binding RNA polymerase—stopping transcription.


Q: What is the MOA of Vancomycin?
A: Inhibits cell wall synthesis by binding to peptidoglycan precursors (not the enzyme like penicillin).


Q: What is the MOA of Bacitracin?
A: Inhibits cell wall synthesis by blocking transport of peptidoglycan subunits across the membrane.


Q: What is Augmentin, and how does it work?
A: A combo of amoxicillin + clavulanic acid.

  • Amoxicillin: inhibits cell wall synthesis

  • Clavulanic acid: inhibits beta-lactamase enzymes, protecting amoxicillin.


Q: What is the MOA of Ciprofloxacin?
A: Inhibits DNA replication by targeting DNA gyrase (topoisomerase II).


Q: What is the MOA of Cephalosporins?
A: Like penicillin, they inhibit cell wall synthesis by targeting transpeptidase enzymes.


Q: What is the MOA of Carbapenems?
A: Broad-spectrum β-lactams; inhibit cell wall synthesis via transpeptidase inhibition, very resistant to β-lactamases.


Let me know if you want these as printable cards or want me to quiz you!