Each nucleotide (monomer) consists of a nitrogenous base (T, A, C, or G),
the sugar deoxyribose, and a phosphate group.
The phosphate of one nucleotide is attached to the sugar of the next, providing a “backbone” from which the bases project.
The 5' end of the polynucleotide is attached to a phosphate, while
the 3' end is attached to a hydroxyl group of the sugar.