Nucleobase

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Chemical structure of base pair bonding. Thymine (T) bonds with adenine (A), and cytosine (C) bonds with guanine (G).

Nucleobase	Nucleoside
Adenine	Adenosine A
Guanine	Guanosine G
Thymine	Thymidine T
Uracil	Uridine U
Cytosine	Cytidine C
Hypoxanthine	Hypoxanthinosine HX
Xanthine	Xanthinosine X

Nucleobases are the parts of RNA and DNA that may be involved in pairing up (see also base pairs). These include cytosine, guanine, adenine, thymine (DNA), uracil (RNA) ans xanthine and hypoxanthine (mutated forms of guanine and, respectively, adenine). These are abbreviated as C, G, A, T, U, X and HX respectively. They are usually simply called bases in Genetics.

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).

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.

[edit] Overall Information

Hypoxanthine and Xanthine are created through Mutagen presence, through De-amination (replacement of the Amine-Group with a Hydroxyl-Group). Hypoxanthine is produced from Adenine, Xanthin from Guanin and Uracil from Cytosin.

Because A, G, C and T appear in the DNA, these molecules are called DNA-bases; A, G, C and U are called respectively RNA-bases.

[edit] Structure

• The "skeleton" of Adenine, Guanin, Hypoxanthine and Xanthine is Purine, hence the name Purin-bases.
• The "skeleton" of Cytosin, Uracil and Thymin is Pyrimidine, hence Pyrimidine-bases.

[edit] See also

• Nucleoside
• Nucleotide
• DNA
• RNA

[edit] External links

• Base pairing in DNA Double Helix (shows specific hydrogen bonds)