Which structural characteristic is typically seen in RNA?

• A. It contains ribose sugar with a 2′ hydroxyl group and uses uracil instead of thymine.
• B. It is usually double-stranded and forms a stable B-form helix throughout the molecule.
• C. It contains ribose sugar but uses thymine rather than uracil.
• D. It contains deoxyribose sugar lacking a 2′ hydroxyl group and uses thymine.

Answer: (A)

Verified step by step guidance

1. Understand the basic structural differences between DNA and RNA, focusing on the sugar component and nitrogenous bases.
2. Recall that RNA contains ribose sugar, which has a hydroxyl group (-OH) attached to the 2' carbon, whereas DNA contains deoxyribose sugar, which lacks this 2' hydroxyl group.
3. Recognize that RNA uses uracil (U) as one of its nitrogenous bases instead of thymine (T), which is found in DNA.
4. Note that RNA is typically single-stranded and can fold into complex secondary structures, unlike the usually double-stranded DNA that forms a stable B-form helix.
5. Combine these points to identify that the characteristic structural feature of RNA is the presence of ribose sugar with a 2' hydroxyl group and the use of uracil instead of thymine.