- A Increasing the rate of transcription occurring at a specifically targeted gene promoter
- B Small interfering RNA (siRNA) binding to mRNA and causing its degradation, silencing a gene
- C Adding methyl groups directly onto cytosine bases located within genomic DNA
- D Permanently and irreversibly blocking ribosomes from translating any mRNA transcript at all
Correct answer: B. Small interfering RNA (siRNA) binding to mRNA and causing its degradation, silencing a gene
Explanation: RNAi: dsRNA triggers RISC complex which unwinds it, using the guide strand to find and cleave complementary mRNA, effectively silencing the gene.
Concept context
GM crops, transgenic animals, gene therapy, molecular diagnostics, and bioethics. Frequent 2–3 mark questions in NEET.