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( Nucleobase)
Nucleobases (or Nucleotide bases) are the parts of RNA and DNA that may be involved in pairing (see also base pairs). These include cytosine, guanine, adenine, thymine (DNA) and uracil (RNA). These are abbreviated as C, G, A, T, and U, respectively. They are usually simply called bases in genetics. Because A, G, C, and T appear in the DNA, these molecules are called DNA-bases; A, G, C, and U are called RNA-bases, respectively. Uracil replaces thymine in RNA. These two bases are identical except that uracil lacks the 5' methyl group. Adenine and guanine belong to the double-ringed class of molecules called purines (abbreviated as R). Cytosine, thymine, and uracil are all pyrimidines (abbreviated as Y). The system of a base covalently bound to the 1' carbon of a ribose or deoxyribose is called a nucleoside, and a nucleoside with one or more phosphate groups attached at the 5' carbon is called a nucleotide. Apart from adenosine (A), cytidine (C), guanosine (G), thymidine (T) and uridine (U), DNA and RNA also contain bases that have been modified after the nucleic acid chain has been formed. In DNA, the only modified base is 5-methylcytidine (m5C). In RNA, there are many modified bases, including pseudouridine (?), dihydrouridine (D), inosine (I), ribothymidine (rT) and 7-methylguanosine (m7G).[1][2]
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Nucleobase Subcategories
Nucleobase Articles
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