How is DNA best defined?

DNA is best defined as a double strand of nucleotides that stores genetic information. Structurally, DNA consists of two long chains of nucleotides twisted into a double helix. Each nucleotide is made up of a sugar, a phosphate group, and a nitrogenous base, and the sequence of these bases encodes the genetic instructions essential for the development and functioning of living organisms. This stored genetic information is crucial for processes such as replication, where DNA is copied prior to cell division, and transcription, where an RNA copy of a gene is made for protein synthesis.

Understanding the role of DNA in heredity and its function in storing and transmitting genetic information is fundamental to biology, as it underpins concepts in genetics, evolution, and molecular biology.