What is the structure of DNA?

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DNA (DeoxyriboNucleic Acid) is a polymer (a molecule made up of many repeated subunits which form a chain). The subunit of DNA is a DNA nucleotide.

The nucleotide is made up of three parts: a deoxyribose sugar, a phosphate group and a nitrate base. There are four types of nitrate base each with a slightly different structure: adenine (A), cytosine (C), guanine (G) and thymine (T).

The deoxyribose and the phosphate form the 'backbone' of the DNA polymer with the nitrate bases sticking off the strand. Two single strands intertwine with each other to form the famous double-helix structure of DNA. The two DNA strands are joined together by hydrogen bonds which form between the nitrogen bases on opposing strands. There is specific base pairing where guanine and cytosine can only bind together and adenine and thymine can only bind together. This can be remember by the word GCAT. The double helix structure of DNA enables it to be more stable and act as an information-carrying molecule. 

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