DNA vs RNA
DNA and RNA are chemically close relatives used for very different jobs.
| DNA | RNA | |
|---|---|---|
| Sugar | deoxyribose | ribose |
| Base | thymine (T) | uracil (U) |
| Usual form | double-stranded | often single-stranded |
| Typical role | durable information archive | message, regulator, structure, catalyst |
The small chemical difference matters. RNA's ribose has an extra 2-prime-OH group. That hydroxyl can participate in cleavage of the phosphodiester backbone, making RNA more prone to hydrolysis than DNA. Removing that oxygen in deoxyribose helps make DNA better suited to long-term information storage.
RNA is not merely "a disposable DNA copy." Messenger RNA carries coding information, but ribosomal RNA forms catalytic/structural machinery, transfer RNA delivers amino acids, and many other RNAs regulate gene expression.
A useful analogy is therefore:
DNA = archive; RNA = working molecular ecosystem built from selected information in the archive.