Final answer:
DNA is composed of repeating subunits called nucleotides, which form polynucleotides. These nucleotides consist of a phosphate group, a five-carbon sugar, and a nitrogenous base, and their arrangement in DNA creates the double helix structure.
Step-by-step explanation:
DNA is a polymer, whose chain is composed of repeating subunits called nucleotides. These nucleotides are the basic building blocks of DNA and RNA
Forming long chains known as polynucleotides. Each nucleotide is made up of three parts: a phosphate group, a five-carbon sugar (ribose in RNA and deoxyribose in DNA), and a nitrogen-containing base.
When nucleotides polymerize, they form the sugar-phosphate backbone of the DNA, with the nitrogenous bases extending from the backbone. In DNA, two chains of nucleotides spiral around each other to create the well-known double helix structure, where hydrogen bonds between complementary bases hold the two strands together.