Each nucleotide has a pentose sugar, a phosphate group and nitrogenous bases like adenine, guanine, cytosine, thymine.
en.wikipedia.org Adenine and guanine are purines, while thymine, cytosine and uracil are pyrimidines.
en.wikipedia.org The particular sequence of the four different types of nucleotides (adenine, cytosine, guanine, and thymine) dictate many characteristics that constitute the organism.
en.wikipedia.org These include bulky, helix distorting damage, such as thymine dimerization and other types of cyclobutyl dimerization caused by UV light as well as single-strand breaks.
en.wikipedia.org During the period 1885 to 1901, he was able to isolate and name its five constituent organic compounds: adenine, cytosine, guanine, thymine, and uracil.
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