What is the primary structural difference between $\mathrm{ribonucleic} \mathrm{acid} \left(\mathrm{RNA}\right)$ and $\mathrm{deoxyribonucleic} \mathrm{acid} \left(\mathrm{DNA}\right)$?

• A. $\mathrm{RNA}$ is double-stranded, whereas $\mathrm{DNA}$ is single-stranded.
• B. $\mathrm{RNA}$ has a ribose sugar, while $\mathrm{DNA}$ has a deoxyribose sugar.
• C. $\mathrm{RNA}$ is more stable than $\mathrm{DNA}$ due to its sugar structure.
• D. $\mathrm{RNA}$ contains uracil instead of thymine.

Answer: (B)

Verified step by step guidance

1. Identify the sugar component in both RNA and DNA. RNA contains ribose sugar, while DNA contains deoxyribose sugar. The key difference is the presence of an -OH group on the 2' carbon in ribose, whereas deoxyribose has an -H at the same position.
2. Examine the nitrogenous bases present in RNA and DNA. RNA contains uracil as one of its bases, whereas DNA contains thymine. This substitution is a primary structural difference between the two nucleic acids.
3. Consider the strand structure of RNA and DNA. RNA is typically single-stranded, allowing it to fold into various shapes, while DNA is usually double-stranded, forming a stable double helix structure.
4. Evaluate the stability of RNA and DNA. DNA is generally more stable than RNA due to the absence of the 2' -OH group, which makes RNA more prone to hydrolysis.
5. Summarize the primary structural differences: RNA has ribose sugar and uracil, is single-stranded, and less stable; DNA has deoxyribose sugar and thymine, is double-stranded, and more stable.