Antibiotic Resistance Mechanisms &
Pharmacology Mastery Exam (150 Questions,
Answers and Rationales)
2025/2026
1. What is antibiotic resistance?
A. Increased immune response to bacteria
B. The ability of bacteria to survive antibiotic exposure
C. Faster drug metabolism in the liver
D. Decreased drug potency
Answer: B
Rationale: Antibiotic resistance occurs when bacteria adapt and
survive despite the presence of antibiotics.
2. Which enzyme breaks down beta-lactam antibiotics?
A. RNA polymerase
B. DNA gyrase
C. Beta-lactamase
D. Topoisomerase IV
Rationale: Beta-lactamase enzymes inactivate beta-lactam
antibiotics by breaking the beta-lactam ring.
3. Which mechanism allows bacteria to pump antibiotics out of the
cell?
A. Target mutation
B. Enzymatic degradation
C. Efflux pumps
D. Cell wall thickening
, Rationale: Efflux pumps actively expel antibiotics from bacterial
cells, reducing intracellular drug concentration.
4. Methicillin-resistant Staphylococcus aureus (MRSA) is resistant
due to:
A. Beta-lactamase production
B. Altered penicillin-binding proteins (PBPs)
C. Increased porin channels
D. Ribosomal subunit destruction
Rationale: MRSA produces altered PBPs that reduce binding of
beta-lactam antibiotics.
5. Which gene is responsible for methicillin resistance in MRSA?
A. blaTEM
B. mecA
C. vanA
D. gyrA
Rationale: The mecA gene encodes PBP2a, leading to beta-
lactam resistance.
6. Vancomycin resistance in Enterococcus (VRE) is due to:
A. Increased drug uptake
B. Alteration of cell wall target from D-Ala-D-Ala to D-Ala-D-Lac
C. Decreased enzyme production
D. Reduced efflux activity
Rationale: The target modification prevents vancomycin from
binding effectively.
7. Which organism commonly produces extended-spectrum beta-
lactamases (ESBLs)?
A. Streptococcus pyogenes
B. Escherichia coli
C. Mycoplasma pneumoniae
, D. Chlamydia trachomatis
Rationale: ESBL production is common in E. coli and Klebsiella
species.
8. What does ESBL stand for?
A. Extended Systemic Beta-Lactam
B. Extra Structural Bacterial Ligase
C. Extended-Spectrum Beta-Lactamase
D. Enhanced Steroid Binding Ligand
Rationale: ESBL enzymes hydrolyze a wide range of beta-lactam
antibiotics.
9. Carbapenem-resistant organisms primarily produce:
A. Penicillinase
B. Carbapenemase
C. RNA polymerase inhibitors
D. Porins
Rationale: Carbapenemases degrade carbapenem antibiotics.
10. A common plasmid-mediated resistance mechanism is:
A. Chromosomal deletion
B. Horizontal gene transfer
C. Mitochondrial mutation
D. Lysosomal digestion
Rationale: Resistance genes are often spread via plasmids
through conjugation.
11. Which process involves bacteria taking up free DNA from the
environment?
A. Conjugation
B. Transduction
C. Transformation
D. Translation
, Rationale: Transformation is the uptake of naked DNA from the
environment.
12. Transduction is mediated by:
A. Plasmids
B. Bacteriophages
C. Ribosomes
D. Mitochondria
Rationale: Bacteriophages transfer genetic material between
bacteria during transduction.
13. Which antibiotic class is most associated with resistance due
to ribosomal protection proteins?
A. Penicillins
B. Tetracyclines
C. Aminoglycosides
D. Glycopeptides
Rationale: Ribosomal protection proteins interfere with
tetracycline binding.
14. What is the main cause of antibiotic resistance
development?
A. Proper antibiotic use
B. Adequate drug dosing
C. Overuse and misuse of antibiotics
D. Improved immune defenses
Rationale: Inappropriate antibiotic use increases selective
pressure for resistant strains.
15. Which drug combination helps overcome beta-lactamase
resistance?
A. Ampicillin + gentamicin
B. Ciprofloxacin + metronidazole
Pharmacology Mastery Exam (150 Questions,
Answers and Rationales)
2025/2026
1. What is antibiotic resistance?
A. Increased immune response to bacteria
B. The ability of bacteria to survive antibiotic exposure
C. Faster drug metabolism in the liver
D. Decreased drug potency
Answer: B
Rationale: Antibiotic resistance occurs when bacteria adapt and
survive despite the presence of antibiotics.
2. Which enzyme breaks down beta-lactam antibiotics?
A. RNA polymerase
B. DNA gyrase
C. Beta-lactamase
D. Topoisomerase IV
Rationale: Beta-lactamase enzymes inactivate beta-lactam
antibiotics by breaking the beta-lactam ring.
3. Which mechanism allows bacteria to pump antibiotics out of the
cell?
A. Target mutation
B. Enzymatic degradation
C. Efflux pumps
D. Cell wall thickening
, Rationale: Efflux pumps actively expel antibiotics from bacterial
cells, reducing intracellular drug concentration.
4. Methicillin-resistant Staphylococcus aureus (MRSA) is resistant
due to:
A. Beta-lactamase production
B. Altered penicillin-binding proteins (PBPs)
C. Increased porin channels
D. Ribosomal subunit destruction
Rationale: MRSA produces altered PBPs that reduce binding of
beta-lactam antibiotics.
5. Which gene is responsible for methicillin resistance in MRSA?
A. blaTEM
B. mecA
C. vanA
D. gyrA
Rationale: The mecA gene encodes PBP2a, leading to beta-
lactam resistance.
6. Vancomycin resistance in Enterococcus (VRE) is due to:
A. Increased drug uptake
B. Alteration of cell wall target from D-Ala-D-Ala to D-Ala-D-Lac
C. Decreased enzyme production
D. Reduced efflux activity
Rationale: The target modification prevents vancomycin from
binding effectively.
7. Which organism commonly produces extended-spectrum beta-
lactamases (ESBLs)?
A. Streptococcus pyogenes
B. Escherichia coli
C. Mycoplasma pneumoniae
, D. Chlamydia trachomatis
Rationale: ESBL production is common in E. coli and Klebsiella
species.
8. What does ESBL stand for?
A. Extended Systemic Beta-Lactam
B. Extra Structural Bacterial Ligase
C. Extended-Spectrum Beta-Lactamase
D. Enhanced Steroid Binding Ligand
Rationale: ESBL enzymes hydrolyze a wide range of beta-lactam
antibiotics.
9. Carbapenem-resistant organisms primarily produce:
A. Penicillinase
B. Carbapenemase
C. RNA polymerase inhibitors
D. Porins
Rationale: Carbapenemases degrade carbapenem antibiotics.
10. A common plasmid-mediated resistance mechanism is:
A. Chromosomal deletion
B. Horizontal gene transfer
C. Mitochondrial mutation
D. Lysosomal digestion
Rationale: Resistance genes are often spread via plasmids
through conjugation.
11. Which process involves bacteria taking up free DNA from the
environment?
A. Conjugation
B. Transduction
C. Transformation
D. Translation
, Rationale: Transformation is the uptake of naked DNA from the
environment.
12. Transduction is mediated by:
A. Plasmids
B. Bacteriophages
C. Ribosomes
D. Mitochondria
Rationale: Bacteriophages transfer genetic material between
bacteria during transduction.
13. Which antibiotic class is most associated with resistance due
to ribosomal protection proteins?
A. Penicillins
B. Tetracyclines
C. Aminoglycosides
D. Glycopeptides
Rationale: Ribosomal protection proteins interfere with
tetracycline binding.
14. What is the main cause of antibiotic resistance
development?
A. Proper antibiotic use
B. Adequate drug dosing
C. Overuse and misuse of antibiotics
D. Improved immune defenses
Rationale: Inappropriate antibiotic use increases selective
pressure for resistant strains.
15. Which drug combination helps overcome beta-lactamase
resistance?
A. Ampicillin + gentamicin
B. Ciprofloxacin + metronidazole
