[Campbell Biology P.1003] Imagine a novel RNA virus evolves that replicates exclusively by pr... | Practice Question

Imagine a novel RNA virus evolves that replicates exclusively by producing single-stranded RNA intermediates, never forming double-stranded RNA during its life cycle. Based on the insect antiviral defense mechanism described, how would this affect the host's ability to combat this specific virus?

  • A: The Dicer-2 enzyme would still be able to recognize and cleave the single-stranded viral RNA, maintaining defense effectiveness.
  • B: The Argo protein complex would initiate the defense by directly binding to the novel single-stranded viral RNA and cleaving it.
  • C: The primary trigger for the insect's antiviral defense, double-stranded RNA, would be absent, potentially rendering this specific defense mechanism ineffective against the virus.
  • D: The host cell would activate an alternative defense pathway involving the synthesis of antibodies against the single-stranded RNA.

Explanation

The insect antiviral defense mechanism relies on the recognition of double-stranded RNA dsRNA by the Dicer-2 enzyme. If the virus never produces dsRNA, the initial trigger for this defense pathway would be absent, rendering it ineffective.