RNA is typically __________.

• A. Double stranded
• B. Single stranded
• C. Triple stranded
• D. Quadruple

Answer: (B)

RNA being single-stranded is what allows it to fold into a variety of shapes and perform many different roles in the cell. Unlike DNA, which is built to stay as a stable double helix, RNA is typically a single chain. Its ribose sugar has a 2'-OH group, which makes long, uniform double-stranded helices less favorable and encourages bending and local base pairing within the same molecule or between RNA molecules. As a result, RNA can form structures like hairpins and other folds that are essential for its functions in processes such as coding, catalysis, and regulation. While RNA can have double-stranded regions, especially in specific contexts or molecules (like certain viral RNAs or RNA interference pathways), its ordinary state is single-stranded.