In the ribose of RNA, unlike DNA, every nucleotide residue has an additional `:`

Options

A. COOH group in 2' position
B. OH group in 5' position
C. OH group in 2' position
D. Phosphate group in 2' position

Answer

To answer the question regarding the differences between ribose in RNA and deoxyribose in DNA, we will analyze the structure of both sugars and identify the key features that distinguish them.

### Step-by-Step Solution:

1. **Identify the Sugars**:
- In DNA, the sugar is **deoxyribose**.
- In RNA, the sugar is **ribose**.

2. **Structure of Ribose and Deoxyribose**:
- **Deoxyribose** has the following structure:
- It contains five carbon atoms (C1, C2, C3, C4, C5).
- At the 2' carbon (C2), there is a hydrogen atom (H).
- **Ribose** has the following structure:
- It also contains five carbon atoms (C1, C2, C3, C4, C5).
- At the 2' carbon (C2), there is a hydroxyl group (–OH) instead of a hydrogen atom.

3. **Key Differences**:
- The main difference between ribose and deoxyribose is the presence of the hydroxyl group (–OH) at the 2' position in ribose, whereas deoxyribose has a hydrogen atom (H) at that position.
- Additionally, ribose has a hydroxyl group (–OH) at the 5' position, while deoxyribose does not have this group.

4. **Conclusion**:
- Therefore, in ribose of RNA, every nucleotide residue has an additional hydroxyl group at the 2' position compared to deoxyribose in DNA. This is a significant structural difference that impacts the stability and functionality of RNA compared to DNA.

### Final Answer:
In the ribose of RNA, unlike DNA, every nucleotide residue has an additional hydroxyl group (–OH) at the 2' position.