Which statement about the poliovirus genome polarity and translation is true?

• A. Negative-sense RNA genome must be transcribed
• B. Positive-sense single-stranded RNA genome acts as mRNA directly
• C. Double-stranded DNA genome
• D. Segmented RNA genome

Answer: (B)

Poliovirus carries a positive-sense single-stranded RNA genome, so its RNA can act directly as messenger RNA in the host cell. When infection occurs, host ribosomes recognize this RNA and start translating it into one long polyprotein. This polyprotein is then cut by viral proteases into the functional viral proteins needed for replication and assembly. The genome is infectious as RNA itself and does not require a transcription step to become mRNA. The translation uses an internal ribosome entry site to initiate without a 5’ cap. This fits a positive-sense RNA virus that is non-segmented and does not use a DNA form.