1. DNA is double-stranded in the form of a double helix, whereas RNA is much more commonly found in single-stranded form.
2. The pentose (5 carbon) sugar found in DNA is deoxyribose, whereas the sugar ribose is found in RNA.
3. DNA contains the base thymine, whereas this is replaced by the base uracil in RNA.
4. DNA is also a much more stable molecule than RNA, due to the lack of a hydroxyl (OH) group on a 2' carbon, which is present in RNA - this hyroxyl group is capable of being involved in hydrolysis reactions that degrade the RNA molecule.