Deoxyribonucleic acid (DNA) is a molecule composed of two chains that are wound together to form a double helix that carries genetic instructions for the development, functioning, growth and reproduction of all known organisms and many viruses. DNA and ribonucleic acid (RNA) are nucleic acids; Together with proteins, lipids and complex carbohydrates (polysaccharides), nucleic acids are one of the four main types of macromolecules that are essential for all known life forms.
