What is the structural difference between the sugar found in $\mathrm{RNA}$ and the sugar found in $\mathrm{DNA}$?

• A. $\mathrm{RNA}$ contains deoxyribose, which has an additional phosphate group, while $\mathrm{DNA}$ contains ribose, which lacks this phosphate group.
• B. $\mathrm{RNA}$ contains deoxyribose, which has a hydroxyl group on the 3' carbon, while $\mathrm{DNA}$ contains ribose, which lacks this hydroxyl group.
• C. $\mathrm{RNA}$ contains ribose, which has a hydroxyl group on the 3' carbon, while $\mathrm{DNA}$ contains deoxyribose, which has an additional methyl group.
• D. $\mathrm{RNA}$ contains ribose, which has a hydroxyl group on the 2' carbon, while $\mathrm{DNA}$ contains deoxyribose, which lacks this hydroxyl group.

Answer: (D)

Verified step by step guidance

1. Identify the sugars present in RNA and DNA. RNA contains ribose, while DNA contains deoxyribose.
2. Understand the structural difference between ribose and deoxyribose. Ribose is a five-carbon sugar with hydroxyl groups (-OH) attached to each carbon.
3. Focus on the 2' carbon of the sugar. In ribose, the 2' carbon has a hydroxyl group (-OH) attached.
4. In deoxyribose, the 2' carbon lacks the hydroxyl group and instead has a hydrogen atom, making it 'deoxy' or lacking oxygen.
5. Conclude that the key structural difference is the presence of a hydroxyl group on the 2' carbon in ribose (RNA) and its absence in deoxyribose (DNA).