DNA strand

A DNA strand, also called a polynucleotide chain, is a linear polymer composed of nucleotide monomers. Each nucleotide consists of a deoxyribose sugar, phosphate group, and one of four nitrogenous bases—adenine (A), cytosine (C), guanine (G), and thymine (T). The backbone is formed by alternating sugar and phosphate groups linked via phosphodiester bonds. Each strand has directionality defined by its chemical ends—5′ phosphate and 3′ hydroxyl. In cells, two complementary antiparallel strands form the iconic double helix structure stabilized by hydrogen bonding between paired bases. The sequence encodes genetic information essential for heredity and cellular function; it serves as both template for its own replication during cell division and for RNA synthesis during gene expression.

Other names

Deoxyribonucleic acid strandPolynucleotide chainDNA chain

Intercalation between base pairs causing disruption of replication/transcription (e.g., doxorubicin); Alkylation/crosslinking of bases leading to strand breaks or mispairing (e.g., cisplatin, cyclophosphamide); Induction of single/double-strand breaks by free radicals or direct cleavage (e.g., bleomycin)