What is DNA?

DNA (deoxyribonucleic acid) is the molecule that carries genetic instructions for life. This guide explains DNA structure, the double helix, nucleotides, and how DNA stores and transmits genetic information.

DNA Structure: The Double Helix

DNA has a double helix structure discovered by Watson and Crick in 1953. Two strands twist around each other like a ladder twisted into a spiral. The sides are sugar-phosphate backbones, and the rungs are nitrogenous base pairs.

The Four Nucleotides

DNA consists of four nucleotide bases: Adenine (A), Thymine (T), Guanine (G), and Cytosine (C). A always pairs with T, and G always pairs with C. This complementary base pairing allows DNA to replicate accurately.

How DNA Stores Information

The sequence of nucleotides encodes genetic information. Genes are specific sequences that code for proteins. The genetic code translates DNA sequences into amino acids, which build proteins that perform cellular functions.