Each nucleotide consists of three parts:

1. A nitrogenous base: These come in five main types: adenine (A), guanine (G), cytosine (C), thymine (T), and uracil (U).

* DNA uses A, G, C, and T.

* RNA uses A, G, C, and U.

2. A five-carbon sugar:

* DNA uses deoxyribose.

* RNA uses ribose.

3. A phosphate group: This provides the backbone of the nucleic acid chain.

The sequence of nucleotides within a nucleic acid chain determines the genetic information it carries.