Ribose and deoxyribose differ in structure around a single carbon, namely

Options

A. C-1
B. C-2
C. C-3
D. C-4

Answer

To determine how ribose and deoxyribose differ in structure, we need to analyze their molecular structures and identify the specific carbon atom where the difference occurs.

### Step-by-Step Solution:

1. **Identify the Structures of Ribose and Deoxyribose**:
- Ribose is a five-carbon sugar (pentose) with the chemical formula C5H10O5. Its structure includes hydroxyl (OH) groups attached to its carbon atoms.
- Deoxyribose is also a five-carbon sugar but has one less oxygen atom than ribose, with the chemical formula C5H10O4.

2. **Draw the Structures**:
- For ribose:
- C1: OH
- C2: OH
- C3: H
- C4: H
- C5: CH2OH
- For deoxyribose:
- C1: OH
- C2: H
- C3: H
- C4: H
- C5: CH2OH

3. **Number the Carbon Atoms**:
- Both sugars have the same numbering for their carbon atoms:
- C1, C2, C3, C4, C5.

4. **Compare the Functional Groups at Each Carbon**:
- At C1: Both have OH.
- At C2: Ribose has OH, while deoxyribose has H.
- At C3: Both have H.
- At C4: Both have H.
- At C5: Both have CH2OH.

5. **Identify the Key Difference**:
- The key difference between ribose and deoxyribose is at C2. Ribose has a hydroxyl group (OH) at C2, while deoxyribose has two hydrogen atoms (H) at C2.

6. **Conclusion**:
- Therefore, ribose and deoxyribose differ in structure around carbon 2 (C2).

### Final Answer:
The correct answer is **C2**.

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