What is DNA?



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  • DNA stands for 'deoxyribonucleic acid' and it is the hereditary material in humans and most other organisms. 
  • The correct structure of DNA was first worked out by Watson and Crick in 1953. DNA contains information in the form of a code made up of four chemical bases: adenine (A), guanine (G), cytosine (C), and thymine (T). Human DNA consists of about 3 billion bases, and more than 99 percent of those bases are the same in all people. DNA is majorly located in the cell nucleus and is called 'nuclear DNA'. However, some amount of DNA is also located in the mitochondria and is called 'mitochondrial DNA' or 'mt DNA'. 
  • DNA is a double helix having a sugar-phosphate backbone like a ladder and the base pairs forming the rungs of the ladder. One turn of the helix is 3.4nm and has 10 base pairs stacked in one such turn. The bases form pairs through hydrogen bonds. 


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