What's the difference between the structure of a nucleic acid and the structure of a protein? ​

There are two principle differences between the structures of proteins and nucleic acids:

Monomer Composition
Eventual Conformation

The first involves the chemical makeup and bonding pattern of individual monomers of each polymer, those monomers being amino acids in proteins and nucleotides in nucleic acids. Amino acids consist of an amine and carboxyl functional group along with a side chain (commonly referred to as an R group), with the amine and carboxyl groups involved in “linking.” Nucleic acids are of quite a different chemical makeup, composed of a five-carbon sugar and phosphate group backbone, both involved in chaining, from which protrudes a nitrogenous base.

The second involves the “destiny” of the polymer in regards to conformation. A protein’s eventual conformation is always consequential, resulting from interactions between the R groups of its amino acid monomers. Nucleic acids, on the other hand, possess the notable structure of strands. RNA’s case is one of a single strand, while DNA’s is a double-helical arrangement of two.
(I know this is a lot of info but I hope it helps :) )