1. A phosphate group: This is a negatively charged molecule that gives DNA its acidic properties.

2. A sugar molecule: In DNA, this is deoxyribose, a five-carbon sugar.

3. A nitrogenous base: There are four different nitrogenous bases in DNA:

* Adenine (A)

* Guanine (G)

* Cytosine (C)

* Thymine (T)

These nucleotides are linked together in a long chain, forming a polynucleotide. The phosphate group of one nucleotide binds to the sugar of the next nucleotide, creating a sugar-phosphate backbone.

The nitrogenous bases stick out from the backbone and are responsible for holding the two DNA strands together. Adenine always pairs with thymine (A-T) and guanine always pairs with cytosine (G-C), forming the famous double helix structure of DNA.