Which of the following feature makes the RNA chemically more reactive and structurally less stable nucleic acid than DNA ?

Options

A. Less rate of mutation.
B. Indirect involvement in protein synthesis
C. Free 2' H group
D. Catalytic nature

Answer

To determine which feature makes RNA chemically more reactive and structurally less stable than DNA, we can analyze the structural differences between the two nucleic acids.

### Step-by-Step Solution:

1. **Identify the Sugars in RNA and DNA**:
- RNA contains ribose sugar, while DNA contains deoxyribose sugar.
- **Ribose** has a hydroxyl (OH) group attached to both the 2' and 3' carbon atoms.
- **Deoxyribose** has a hydroxyl (OH) group only at the 3' carbon and lacks the hydroxyl group at the 2' carbon.

2. **Analyze the Impact of the 2' Hydroxyl Group**:
- The presence of the hydroxyl group at the 2' position in ribose makes RNA more reactive.
- This 2' OH group can act as a nucleophile, which means it can participate in chemical reactions more readily.

3. **Understand the Mechanism of Reactivity**:
- In RNA, the 2' OH can attack the phosphate group in the phosphodiester bond, leading to the cleavage of this bond.
- This reaction results in the breakdown of the RNA molecule, contributing to its instability.

4. **Compare Stability**:
- Because RNA can easily undergo hydrolysis due to the reactive 2' OH group, it is less stable compared to DNA, which lacks this reactive group.
- DNA, with its deoxyribose sugar, is more stable as it does not have the reactive 2' OH group.

5. **Conclusion**:
- The feature that makes RNA chemically more reactive and structurally less stable than DNA is the presence of the free hydroxyl group at the 2' position of the ribose sugar.

### Final Answer:
The correct answer is: **The free 2' hydroxyl (OH) group in RNA.**

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