Describe the structure of DNA, including the type of monomers it is made from, and explain how the structure of a polypeptide differs from the structure of DNA.

DNA is a polymer made from nucleotide monomers.
Each nucleotide contains a phosphate group, a pentose sugar (deoxyribose) and one of four nitrogenous bases: adenine, thymine, cytosine or guanine.
The four nucleotides link via phosphodiester bonds to form two complementary strands that coil into a right‑handed double helix.
A polypeptide, by contrast, is a polymer of amino acid monomers, not nucleotides. It consists of a single chain of amino acids linked by peptide bonds, whereas DNA is a double‑stranded helix.