DNA is fundamental to the biology of all life on Earth, but how many of us actually know what it is or what it's made of?

The structure of a nucleotide, consisting of a phosphate group (left), a ... adenine (A), guanine (G), cytosine (C), or uracil (U). Uracil replaces thymine in RNA. Ribonucleotides can be further ...

Uracil is often compared to thymine (T), which is the nucleobase that ... meaning it has the same chemical formula but a different structure. It is often referred to as the "fifth nucleotide" due to ...