DNA, or deoxyribonucleic acid is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms. The main role of DNA molecules is the long-term storage of information. DNA is often compared to a set of blueprints or a recipe, or a code, since it contains the instructions needed to construct other components of cells, such as proteins and RNA molecules.
Chemically, DNA consists of two long polymers of simple units called nucleotides, with backbones made of sugars and phosphate groups. Attached to each sugar is one of four types of molecules called bases. The four bases found in DNA are adenine (abbreviated A), cytosine (C), guanine (G) and thymine (T). It is the sequence of these four bases along the backbone that encodes information.
DNA is found in almost every cell within the human body from white cells in the blood to check cells in your mouth. Once the sequence of your DNA has been determined, it does not change over your lifetime.
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