Deoxyribonucleic acid

DNA, or deoxyribonucleic acid, is the hereditary material in humans and almost all other organisms Almost every cell in the body of someone having the same DNA Most DNA is found in the nucleus of the cell (which is called nuclear DNA), but small amounts of DNA can also be found in the mitochondria (where it is called mitochondrial DNA or medina)

The information in DNA is stored as a code which consists of four chemical bases: adenine (A), guanine (G), cytosine (C) and thymine (T) Human DNA contains about 3 billion bases, and more than 99 percent of their base is the same in all people The order or sequence of these bases determines the information available for building and maintaining an organism, similar to the way in which letters appear in a certain sequence to form words and sentences

DNA base pairs with each other, A with T and C with G, to form units called base pairs Each base is also linked to a molecule of sugar and phosphate molecules Together, the base, sugar and phosphate called nucleotides Nucleotides are arranged in two long grooves that form a spiral called a double helix Double helix structure is a bit 'like a ladder with the base pairs that make up the rung of the ladder and sugar and phosphate molecules forming the vertical arm of the scale

An important property of DNA that can replicate or make copies of itself Each double-stranded DNA can serve as a model for the duplication of DNA sequence This is important when cells divide because each new cell needs to have proper copies of DNA present in older cells