Describe the role of the sugar molecule in the structure of nucleic acids and Explain how its variation between DNA and RNA affects the function of each type of nucleic acid.

The sugar in nucleic acids is a five‑carbon pentose that forms the backbone of the polymer.
1. It links to a phosphate group to give a repeating –5′‑phosphate‑sugar‑3′ chain.
2. In DNA the sugar is deoxyribose (2′‑deoxyribose).
3. In RNA the sugar is ribose (2′‑hydroxyl).
4. The 2′‑hydroxyl in ribose makes RNA more chemically reactive and less stable, allowing it to adopt diverse secondary structures and act as a catalyst or messenger; the absence of the 2′‑OH in deoxyribose gives DNA a more stable, double‑stranded structure suited for long‑term storage of genetic information.