A polymer composed of two polynucleotide chains that coil around each other to form a double helix, DNA carries genetic instructions for the development, functioning, growth, and reproduction of all known organisms and many viruses. The two DNA strands are known as polynucleotides as they are composed of simpler monomeric units called nucleotides. Each nucleotide is composed of one of four nitrogen-containing nucleobases (cytosine [C], guanine [G], adenine [A] or thymine [T]), a sugar called deoxyribose, and a phosphate group. The nucleotides are joined to one another in a chain by covalent bonds.
DNA Structure
DNA is located in the nucleus of cells in the form of a double-stranded helix and consists of four chemical bases: Adenine (A), Thymine (T), Cytosine (C), and Guanine (G). The sequence of these bases determines the genetic code that is used to create proteins and other molecules necessary for the function and growth of living organisms.
Applications of DNA
Today, DNA analysis is used in a wide range of applications, including forensics, medicine, agriculture, and evolutionary biology. The discovery of DNA's structure and function in the mid-20th century revolutionized biology and genetics, enabling scientists to understand how genetic information is passed from one generation to the next and how variations in DNA contribute to differences between individuals and species.
Types of Nucleic Acids
Alongside proteins, lipids, and complex carbohydrates (polysaccharides), nucleic acids are one of the four major types of macromolecules that are essential for all known forms of life. DNA and ribonucleic acid (RNA) are nucleic acids.
