DNAstreng

DNAstreng, or DNA strand, refers to a molecule of deoxyribonucleic acid that stores the genetic information essential for the growth, development, and functioning of living organisms. In most organisms, DNA exists as a double-stranded molecule that forms a right-handed double helix. Each strand is a long polymer of nucleotides, composed of a sugar-phosphate backbone and nitrogenous bases: adenine, thymine, cytosine, and guanine. Bases on opposite strands pair specifically (A with T, C with G) through hydrogen bonds, creating complementary strands that run in opposite directions (antiparallel).

The sequence of bases along a DNA strand encodes genetic information. This information is used during transcription to produce RNA, which in turn guides protein synthesis. During cell division, DNA is replicated in a semiconservative manner: the two strands separate and each serves as a template for a new complementary strand, with the help of enzymes such as helicase, DNA polymerase, primase, ligase, and topoisomerase.

In eukaryotes, DNA is packaged into chromosomes within chromatin, with DNA wound around histone proteins to form nucleosomes. This organization enables efficient packaging of long molecules and regulates access to genetic information. DNA length is measured in base pairs, kilobases, or megabases. Telomeres protect chromosome ends, while circular DNA is common in bacteria and some organelles.

DNA integrity is maintained by repair pathways such as base excision repair and nucleotide excision repair. Mutations in the DNA sequence can alter gene function and contribute to variation, disease, or adaptation. DNA strands are foundational to genetics, biotechnology, and forensic science.