What are the building blocks of DNA and RNA?

The building blocks of DNA and RNA are nucleotides. Nucleotides are organic molecules composed of three components: a nitrogenous base, a five-carbon sugar, and a phosphate group. In DNA, the sugar is deoxyribose, while in RNA, the sugar is ribose. The specific arrangement of the nitrogenous bases (adenine, thymine, cytosine, and guanine for DNA; adenine, uracil, cytosine, and guanine for RNA) determines the genetic information encoded in these molecules.

While amino acids are the building blocks of proteins and are crucial in the process of translation, they do not play a direct role in the structure of nucleic acids. Sugars and phosphates are components of nucleotides but cannot be considered the basic building blocks on their own, as they need to be combined with nitrogenous bases to form nucleotides. Proteins are also distinct from nucleotides and serve different functions in the cell. Therefore, nucleotides, encompassing all three components, are the fundamental units that form the structures of both DNA and RNA.