The four types of nucleotides that make up DNA are named for their nitrogenous bases.

Here's a breakdown:

* Adenine (A)

* Guanine (G)

* Cytosine (C)

* Thymine (T)

Each nucleotide consists of three parts:

1. Deoxyribose sugar: A five-carbon sugar.

2. Phosphate group: A molecule containing phosphorus.

3. Nitrogenous base: This is the part that gives each nucleotide its unique identity and is what they're named for.

The nitrogenous bases are responsible for the specific pairing of nucleotides in DNA (A with T, and G with C), which is crucial for the molecule's structure and function.