Which structural feature is unique to the sugar found in $\mathrm{RNA}$ compared to $\mathrm{DNA}$?

• A. The presence of an aldehyde group on the $1^{\prime }$ carbon
• B. The presence of a hydroxyl group on the $2^{\prime }$ carbon
• C. The presence of a phosphate group on the $3^{\prime }$ carbon
• D. The presence of a methyl group on the $5^{\prime }$ carbon

Answer: (B)

Verified step by step guidance

1. Identify the sugars present in RNA and DNA: RNA contains ribose, while DNA contains deoxyribose.
2. Examine the structural differences between ribose and deoxyribose: Ribose has a hydroxyl group (-OH) on the 2' carbon, whereas deoxyribose lacks this hydroxyl group, having only a hydrogen atom at the 2' position.
3. Understand the significance of the 2' carbon: The presence of the hydroxyl group on the 2' carbon in ribose is a key structural feature that distinguishes RNA from DNA.
4. Consider the options provided: Evaluate each option to determine which structural feature is unique to RNA's sugar.
5. Conclude that the presence of a hydroxyl group on the 2' carbon is the unique feature of the sugar in RNA compared to DNA.