Which of the following is true about RNAi process ?

Options

A. It is a method of cellular defense.
B. It involves silencing of a specific mRNA due to a complementary RNA molecule.
C. The source of complementary RNA in this process may be infection by viruses having RNA genomes.
D. All are true

Answer

To solve the question regarding the RNA interference (RNAi) process, we will analyze each statement provided in the options to determine their validity.

### Step-by-Step Solution:

1. **Understanding RNAi**:
- RNA interference (RNAi) is a biological process in which RNA molecules inhibit gene expression or translation, by neutralizing targeted mRNA molecules.

2. **Analyzing the First Statement**:
- **Statement**: "It is a method of cellular defense."
- **Explanation**: RNAi acts as a defense mechanism in cells, particularly against viral infections and transposons. This statement is **true**.

3. **Analyzing the Second Statement**:
- **Statement**: "It involves silencing of the specific messenger RNA due to complementary RNA molecule."
- **Explanation**: The process involves the binding of small interfering RNA (siRNA) or microRNA (miRNA) to complementary mRNA, leading to its degradation or inhibition of translation. This statement is **true**.

4. **Analyzing the Third Statement**:
- **Statement**: "The source of complementary RNA in this process may be infection by viruses having RNA genomes."
- **Explanation**: RNA viruses can introduce RNA into the host cell, which can then trigger the RNAi pathway as a response. This statement is also **true**.

5. **Conclusion**:
- Since all the statements provided in the options are true regarding the RNA interference process, the correct answer is that **all are true**.

### Final Answer:
**All are true about the RNAi process.**

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