Top 30 MCQs on Antibiotics with Answers & Explanation

 📌Introduction  

Antibiotics are one of the most important topics in pharmacology and are frequently asked in exams like GPAT, DSSSB, and other pharmacy competitive exams. These MCQs will help you revise important concepts like classification, mechanism, uses, and resistance.

🧬 MCQs on Antibiotics  

1. Antibiotics are used to treat:  

A) Viral infections  

B) Bacterial infections  

C) Fungal infections  

D) Parasitic infections  

✔ Answer: B) Bacterial infections  

➜ Explanation: Antibiotics act only against bacteria.

2. Which is a bactericidal drug?  

A) Penicillin  

B) Tetracycline  

C) Erythromycin  

D) Chloramphenicol  

✔ Answer: A) Penicillin  

➜ Explanation: It kills bacteria by inhibiting cell wall synthesis.

3. Penicillin acts by inhibiting:  

A) Protein synthesis  

B) DNA synthesis  

C) Cell wall synthesis  

D) Metabolism  

✔ Answer: C) Cell wall synthesis  

4. Tetracycline inhibits:  

A) DNA synthesis  

B) Protein synthesis  

C) Cell wall synthesis  

D) RNA synthesis  

✔ Answer: B) Protein synthesis  

5. Ciprofloxacin acts on:  

A) Ribosome  

B) DNA gyrase  

C) Cell wall  

D) Enzymes  

✔ Answer: B) DNA gyrase  

6. Sulfonamides act as:  

A) Protein inhibitors  

B) Cell wall inhibitors  

C) Antimetabolites  

D) Hormones  

✔ Answer: C) Antimetabolites  

7. Which antibiotic is used in tuberculosis?  

A) Amoxicillin  

B) Rifampicin  

C) Ibuprofen  

D) Paracetamol  

✔ Answer: B) Rifampicin  

8. Macrolides act on:  

A) Cell wall  

B) Protein synthesis  

C) DNA  

D) Hormones  

✔ Answer: B) Protein synthesis  

9. Aminoglycosides are:  

A) Bacteriostatic  

B) Bactericidal  

C) Antifungal  

D) Antiviral  

✔ Answer: B) Bactericidal  

10. Chloramphenicol inhibits:  

A) 30S ribosome  

B) 50S ribosome  

C) DNA  

D) Cell wall  

✔ Answer: B) 50S ribosome  

11. Which antibiotic causes teeth discoloration?  

A) Penicillin  

B) Tetracycline  

C) Ciprofloxacin  

D) Rifampicin  

✔ Answer: B) Tetracycline  

12. Which is NOT an antibiotic?  

A) Penicillin  

B) Ciprofloxacin  

C) Paracetamol  

D) Rifampicin  

✔ Answer: C) Paracetamol  

13. Antibiotics should be avoided in:  

A) Bacterial infection  

B) Viral infection  

C) Fever  

D) Pain  

✔ Answer: B) Viral infection  

14. Resistance occurs due to:  

A) Proper use  

B) Overuse  

C) Correct dose  

D) Full course  

✔ Answer: B) Overuse  

15. Which inhibits DNA replication?  

A) Penicillin  

B) Ciprofloxacin  

C) Tetracycline  

D) Erythromycin  

✔ Answer: B) Ciprofloxacin  

16. Erythromycin belongs to:  

A) Penicillin  

B) Macrolide  

C) Aminoglycoside  

D) Tetracycline  

✔ Answer: B) Macrolide  

17. Which is bacteriostatic?  

A) Penicillin  

B) Aminoglycosides  

C) Tetracycline  

D) Cephalosporin  

✔ Answer: C) Tetracycline  

18. Cephalosporins act on:  

A) Protein  

B) Cell wall  

C) DNA  

D) RNA  

✔ Answer: B) Cell wall  

19. Superinfection is due to:  

A) Low dose  

B) Destruction of normal flora  

C) High immunity  

D) Infection  

✔ Answer: B) Destruction of normal flora  

20. Antibiotics may cause:  

A) Allergy  

B) Growth  

C) Energy  

D) Sleep  

✔ Answer: A) Allergy  

21. Which is broad-spectrum antibiotic?  

A) Penicillin G  

B) Tetracycline  

C) Rifampicin  

D) Vancomycin  

✔ Answer: B) Tetracycline  

22. Which is narrow spectrum?  

A) Penicillin G  

B) Tetracycline  

C) Chloramphenicol  

D) Ciprofloxacin  

✔ Answer: A) Penicillin G  

23. Fluoroquinolones act on:  

A) DNA  

B) Protein  

C) Cell wall  

D) Metabolism  

✔ Answer: A) DNA  

24. Which antibiotic is nephrotoxic?  

A) Aminoglycosides  

B) Penicillin  

C) Tetracycline  

D) Macrolide  

✔ Answer: A) Aminoglycosides  

25. Which is used in UTI?  

A) Ciprofloxacin  

B) Insulin  

C) Aspirin  

D) Vitamin D  

✔ Answer: A) Ciprofloxacin  

26. Which causes ototoxicity?  

A) Aminoglycosides  

B) Penicillin  

C) Macrolides  

D) Sulfonamides  

✔ Answer: A) Aminoglycosides  

27. Which is a macrolide?  

A) Erythromycin  

B) Penicillin  

C) Ciprofloxacin  

D) Tetracycline  

✔ Answer: A) Erythromycin  

28. Which antibiotic affects bone growth?  

A) Tetracycline  

B) Penicillin  

C) Rifampicin  

D) Amoxicillin  

✔ Answer: A) Tetracycline  

29. Antibiotics act on:  

A) Viruses  

B) Bacteria  

C) Fungi  

D) Parasites  

✔ Answer: B) Bacteria  

30. Best use of antibiotics:  

A) Viral fever  

B) Bacterial infection  

C) Pain  

D) Diabetes  

✔ Answer: B) Bacterial infection  

📝  Conclusion  

These 30 MCQs on antibiotics will help you strengthen your pharmacology concepts and improve your exam performance. Practice regularly for better results in GPAT and DSSSB exams.

👉 Read detailed notes here: https://pharmacymcq.in/antibiotics-classification-mechanism-uses-side-effects/

Read more