UPSC Prelims 2025 PYQ on Viruses and Marine Biology
Q. Consider the following statements:
I. No virus can survive in ocean waters. II. No virus can infect bacteria. III. No virus can change the cellular transcriptional activity in host cells.
How many of the statements given above are correct?
✅ Correct Answer: (d) None
Explanation:
Statement I: ❌ Incorrect. Viruses are abundant in ocean waters—estimated at over 10³⁰ in number. Most are bacteriophages that infect marine bacteria and play vital roles in nutrient and carbon cycling.
Statement II: ❌ Incorrect. Bacteriophages are viruses that specifically infect bacteria. They are even used in medical treatments like phage therapy for antibiotic-resistant infections.
Statement III: ❌ Incorrect. Viruses alter host cell transcriptional activity to favor viral gene expression and replication by hijacking the host’s molecular machinery.
