Both DNA and RNA are composed of the same monomer unit – nucleotides. These nucleotides are composed of three parts:
- A phosphate group
- A pentose sugar
- A nitrogenous base
This also happens to be the order of the nucleotide. However, there are differences between the nucleotides in DNA and RNA. The table below demonstrates this.
| DNA | RNA |
| Pentose sugar is deoxyribose | Pentose sugar is ribose |
| Nitrogenous bases: adenine, thymine, cytosine and guanine | Nitrogenous bases: adenine, uracil, cytosine and guanine |
Although deoxyribose and ribose are both pentose sugars, the key difference is that ribose has one more oxygen than deoxyribose.