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?

(a) Only one
(b) Only two
(c) All the three
(d) None

The correct answer is (d) None.

All three statements are factually incorrect.

Explanation

I. No virus can survive in ocean waters.
- This is incorrect. The ocean is teeming with viruses. Marine viruses are the most abundant biological entities in the ocean, estimated to number in the nonillions ([latex]10^{30}[/latex]). They play a crucial role in marine ecosystems by infecting all types of marine life, especially bacteria.
II. No virus can infect bacteria.
- This is incorrect. Viruses that infect bacteria are called bacteriophages (or “phages”). This is a fundamental concept in biology. A bacteriophage attaches to a bacterium and injects its genetic material, hijacking the cell to produce more viruses.
III. No virus can change the cellular transcriptional activity in host cells.
- This is incorrect. This is precisely what viruses do to replicate. A virus is an obligate parasite, meaning it must take over a host cell. It redirects the host’s transcriptional activity (the process of making RNA from a DNA template) to stop making host proteins and start making viral proteins, thus completely changing the cell’s normal function.

Learn More

The Viral World

Marine Viruses: The sheer number of viruses in the ocean is staggering. They are a major driver of nutrient cycling. By bursting host cells (like bacteria), they release organic matter (carbon, nitrogen, phosphorus) back into the water, which can then be used by other microorganisms. This is known as the “viral shunt.”
Bacteriophages (“Phages”): The name literally means “bacteria eaters.” These viruses are highly specific, meaning a particular phage will only infect a specific type or strain of bacteria. This property is being heavily researched for “phage therapy,” a potential alternative to antibiotics for treating drug-resistant bacterial infections.
Viral Hijacking: When a virus (like influenza or HIV) infects a human cell, its primary goal is to force that cell to read its genetic “blueprint” (DNA or RNA) instead of the cell’s own. It uses its own proteins to take over the cell’s transcription machinery, effectively turning the cell into a dedicated virus-making factory.