Answer: Antibiotics target structures unique to bacteria (cell wall, ribosomes) that are absent in human cells, killing bacteria without harming the host.
- A Antibiotics act mainly by directly destroying viral capsids and degrading viral genetic material inside infected host cells as frequently observed in practice
- B Antibiotics target structures unique to bacteria (cell wall, ribosomes) that are absent in human cells, killing bacteria without harming the host
- C Antibiotics work mainly by generally strengthening the host's own innate and adaptive cellular immune defenses over time in many documented cases
- D Antibiotics are considered equally effective treatments against most bacterial, viral, and fungal infections alike according to conventional understanding
Correct answer: B. Antibiotics target structures unique to bacteria (cell wall, ribosomes) that are absent in human cells, killing bacteria without harming the host
Explanation: Antibiotics exploit differences between bacterial and human cells: beta-lactams (penicillin) target bacterial cell wall (peptidoglycan); tetracyclines target bacterial 70S ribosomes; fluoroquinolones target bacterial DNA gyrase. These targets are absent or different in human cells, providing selective toxicity.
The Plasmodium parasite needs both hosts: the female Anopheles mosquito injects sporozoites while biting (infecting the human liver and RBCs, causing the malaria fever cycle), then picks up gametocytes from an infected person's blood, completing the parasite's sexual stage inside the mosquito.
Concept context
Pathogens, infectious diseases, non-infectious diseases, drugs, cancer, and public health. High NEET importance.