JEE Main 2026 — Biomolecules Question with Solution

DNA and RNA are chiral molecules due to their structural components. Both contain pentose sugars: DNA contains deoxyribose and RNA contains ribose. These are D-sugars with multiple chiral centers (at $C_2$, $C_3$, and $C_4$ in the furanose ring). The D-designation comes from the stereochemical configuration at the chiral center furthest from the carbonyl carbon. The chiral centers in these sugar moieties are the primary source of chirality in nucleic acids, making them optically active molecules. While the phosphate units and bases also contribute to molecular structure, the fundamental chirality arises from the D-sugar component.