Consider the following statements:

1. No virus can survive in ocean waters.
2. No virus can infect bacteria.
3. No virus can change the cellular transcriptional activity in host cells.

How many of the statements given above are correct?

1. Only one
2. Only two
3. All three
4. None

Explanation

Statement I is incorrect

• The ocean is full of viruses, particularly bacteriophages, which infect marine bacteria. In fact, viruses are the most abundant biological entities in the ocean, playing a key role in regulating microbial populations and nutrient cycling.

Statement II is incorrect

• Bacteriophages (or simply phages) are viruses that specifically infect bacteria. They are extensively studied in molecular biology and even used in phage therapy as an alternative to antibiotics.

Statement III is incorrect

• Viruses commonly alter host cells’ transcriptional machinery to replicate their genetic material. E.g., HIV and many other viruses hijack the host cell’s transcription system for viral gene expression.

Answer: (d) None; Difficulty Level: Easy