Question

A virus-X requires endocytosis for infection and replicates in the cytosol. De-proteinized genome of the virus is non-infectious. X is a

• A. Retrovirus
• B. Enveloped plus-strand RNA virus
• C. Bacteriophage
• D. Enveloped minus-strand RNA virus

Hint:

Minus-strand RNA is like a mirror image; the cell can't read it without the special viral "translator" protein.

Answer 1

The Correct Option is D

Step 1: Concept
The infectivity of a de-proteinized (naked) genome depends on whether the cell can immediately translate it.

Step 2: Analysis
Plus-strand RNA (+RNA) is equivalent to mRNA and is infectious on its own. However, minus-strand RNA (-RNA) must be copied into +RNA by a viral-specific RNA-dependent RNA polymerase carried inside the virion.

Step 3: Reasoning
If the genome is de-proteinized, this essential enzyme is lost. Therefore, -RNA genomes are non-infectious when naked.

Step 4: Conclusion
The description fits an enveloped minus-strand RNA virus. Final Answer: (D)