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 understand the difference between ribose and deoxyribose, we need to analyze their structures, particularly focusing on the carbon atoms.

### Step-by-Step Solution:

1. **Identify the Sugar Type**:
- Ribose and deoxyribose are both pentose sugars, meaning they each contain five carbon atoms.

2. **Draw the Basic Structure**:
- Start by drawing a five-carbon ring structure for both sugars. Each carbon atom will be numbered from 1 to 5.

3. **Add Hydroxyl Groups (OH)**:
- In ribose, each of the carbon atoms (except for the carbonyl carbon) will have a hydroxyl group (–OH) attached to them.
- For ribose, the structure can be represented as:
- C1: –OH
- C2: –OH
- C3: –OH
- C4: –OH
- C5: –CH2OH

4. **Identify the Key Difference**:
- The critical difference between ribose and deoxyribose lies at carbon number 2.
- In ribose, carbon 2 has a hydroxyl group (–OH).
- In deoxyribose, carbon 2 has a hydrogen atom (–H) instead of a hydroxyl group.

5. **Conclude the Difference**:
- Therefore, ribose has the formula C5H10O5, while deoxyribose has the formula C5H10O4. The absence of one oxygen atom in deoxyribose (specifically at carbon 2) is what gives it the name "deoxy," meaning "without oxygen."

### Final Answer:
Ribose and deoxyribose differ in structure around carbon number 2, where ribose has a hydroxyl group (–OH) and deoxyribose has a hydrogen atom (–H).

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