Viroids differ from viruses

Options

A. in absence of RNA
B. in the presence of DNA
C. in the absence of a protein coat
D. in the presence of nucleic acid and protein

Answer

**Step-by-Step Solution:**

1. **Understanding Viruses:**
- Viruses are infectious agents that can cause diseases. They contain genetic material, which can be either DNA or RNA. This genetic material can exist in two forms: double-stranded or single-stranded.
- The genetic material of viruses is enclosed in a protective protein coat known as a capsid.

2. **Understanding Viroids:**
- Viroids are distinct from viruses as they are composed solely of RNA. They are referred to as "free RNA molecules" because they lack a protein coat.
- Unlike viruses, viroids do not have any protective covering around their genetic material.

3. **Comparing Viroids and Viruses:**
- The key difference is that viruses have either DNA or RNA enclosed in a protein coat (capsid), while viroids consist only of RNA without any protein covering.
- This absence of a protein coat is a significant distinguishing feature between the two.

4. **Evaluating the Options:**
- The question provides several options to differentiate viroids from viruses:
- Option 1: "In absence of RNA" - Incorrect, as viroids contain RNA.
- Option 2: "In the presence of DNA" - Incorrect, as viroids only have RNA, not DNA.
- Option 3: "In the absence of protein coat" - Correct, as viroids do not have a protein coat.
- Option 4: "In the presence of nucleic acid and protein" - Incorrect, as viroids only have nucleic acid (RNA) and no protein.

5. **Conclusion:**
- The correct answer to the question "Viroids differ from viruses" is Option 3: "In the absence of protein coat."

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