All Exams Test series for 1 year @ ₹349 only
Question

The antibiotic penicillin can kill invading bacteria without harming human cells because it targets bacterial :

This question was previously asked in
CDS 2 2026 Maths Question Paper (13-Sep-2026)
The correct answer is
Cell wall

The question asks about the specific component that penicillin targets in bacteria, which is absent in human cells, explaining its selective toxicity.

Penicillin's Selective Action Mechanism

Penicillin works by interfering with the synthesis of the bacterial cell wall. This rigid outer layer is essential for the survival of many bacteria, protecting them from osmotic lysis and maintaining their shape.

Why Human Cells Are Unaffected

  • Human cells do not possess a cell wall. They are eukaryotic cells surrounded only by a plasma membrane.
  • Since penicillin's target (the cell wall) is unique to bacteria, it does not affect human cells, making it a safe and effective antibiotic.

Analysis of Options

  • Cell wall: Bacteria have a peptidoglycan cell wall that penicillin inhibits. Human cells lack this structure. This is the correct target.
  • Plasma membrane: Both bacteria and human cells have a plasma membrane. Penicillin does not primarily target this structure.
  • Ribosome: Bacteria have 70S ribosomes, while human cells have 80S ribosomes. Some antibiotics target ribosomes, but this is not penicillin's primary mechanism.
  • Chromosome: Both cell types contain chromosomes (genetic material), but penicillin does not directly target them.

Therefore, penicillin targets the bacterial cell wall.

Was this answer helpful?

Similar Questions

  1. Which one of the following is an example of airborne disease?
  2. Which one among the following pairs of diseases and their types is not correctly matched ?

Important Questions from Human Diseases

  1. Consider the following diseases: 

    (1) Diphtheria 

    (2) Chickenpox 

    (3) Smallpox 

    Which of the above diseases has/have been eradicated in India?

  2. Consider the following statements : 

    1. Hepatitis B is several times more infectious than HIV / AIDS 

    2. Hepatitis B can cause liver cancer. 

    Which of the statements given above is/ are correct?

  3. With reference to the treatment of cancerous tumours, a tool called cyberknife has been making the news. In this context, which one of the following statements is not correct?

  4. With regard to the transmission of the Human Immune deficiency Virus, which one of the following statements is not correct?

  5. Which instrument is used to measure the blood pressure manually?

Need Expert Advice?
Test Series
CDS img
Defence
UPSC CDS 2026 Mock Test Series
536 Tests 4 Tests Free
1647 Attempts
4.3(174)
English, Hindi
More Questions from CDS

Start Your Preparation with Prepp Mobile App

Download the app from Google Play & App Store
Download the app from Google Play & App Store
Prepp Mobile App