Question

RNAi mediated RNA interference mediates which of the following?

• A. RNA quelling
• B. RNA ligation
• C. RNA silencing
• D. RNA inversion

Hint:

Remember:
• siRNA and miRNA are involved in RNA interference
• RNAi blocks gene expression by degrading or inhibiting mRNA \[ \text{RNA interference} = \text{Post-transcriptional gene silencing} \]

Answer 1

The Correct Option is C

Concept: RNA interference (RNAi) is a biological process in which small RNA molecules inhibit gene expression by targeting specific messenger RNA (mRNA) molecules. This process results in: \[ \text{Gene silencing or RNA silencing} \] RNAi plays important roles in:
• Regulation of gene expression
• Antiviral defense
• Genome stability Small interfering RNAs (siRNA) and microRNAs (miRNA) are major molecules involved in RNA interference.

Step 1: Understanding the function of RNA interference. In RNAi:
• Double-stranded RNA is processed into small RNA fragments.
• These fragments bind complementary mRNA.
• Target mRNA is degraded or translation is inhibited. Thus: \[ \boxed{\text{RNAi mediates RNA silencing}} \]

Step 2: Understanding why RNA silencing occurs. When mRNA is destroyed or blocked: \[ \text{Protein synthesis decreases} \] As a result: \[ \text{Gene expression is silenced} \] Hence, RNA interference is also known as: \[ \text{Post-transcriptional gene silencing} \]

Step 3: Eliminating the incorrect options.
• Option (A): RNA quelling is a related phenomenon in fungi but not the general term mediated by RNAi.
• Option (B): RNA ligation refers to joining RNA molecules and is unrelated to RNA interference.
• Option (D): RNA inversion is not associated with RNAi. Therefore, the correct answer is RNA silencing. \[ \boxed{\text{RNAi} \Rightarrow \text{RNA silencing}} \]