
{| border="1" cellpadding="2" cellspacing="0" align="right" style="margin-left:1em" ! colspan="2" align=center bgcolor="#cccccc" | Cytosine |- | IUPAC nomenclature | 4-Aminopyrimidin-2(1''H'')-one |- | Chemical formula | C4H5N3O |- | Molecular mass | 111.10 g/mol |- | Melting point | 320 - 325 °C (decomp) |- | CAS registry number | 71-30-7 |- | Simplified molecular input line entry specification | NC1=NC(NC=C1)=O |- | colspan="2" align="center" | |- |} Cytosine is one of the 5 main nucleobases used in storing and transporting genetic information within a cell in the nucleic acids DNA and RNA. It is a pyrimidine derivative, with a heterocyclic aromatic ring and two substituents attached (an amine group at position 4 and a Ketone group at position 2). The nucleoside of cytosine is cytidine. Cytosine was first discovered in 1894 when it was isolated from calf thymus tissues. A structure was proposed in 1903, and was synthesized (and thus confirmed) in the laboratory in the same year. Cytosine can be found as part of DNA, RNA, or as a part of a nucleotide. As cytosine triphosphate (CTP), it can act as a co-factor to enzymes, and can transfer a phosphate to convert adenosine diphosphate (ADP) to adenosine triphosphate (ATP). In DNA and RNA, cytosine is paired with guanine. However, it is inherently unstable, and can change into uracil (deamination). This can lead to a point mutation if not repaired by the DNA repair enzymes. Cytosine can also be methylated into 5-methylcytosine by an enzyme called DNA methyltransferase. Pyrimidines
Cytosine is defined here as "one of 5 main nucleobases..." As one of four bases in DNA, the other 3 (Guanine, Adenine and Thymine) are each defined as "one of 4 main nitrogenous bases..." Though it is true that in RNA, Uracil replaces Thymine, it (uracil) is also defined as "one of the 4 main nitrogenous bases..." I wonder if Cytosine should be changed to also be defined as "one of 4 main nitrogenous bases" to make it consistent with the other bases, though the article for "nitrogenous base" might need to be modified to further clarify the 4 main bases in DNA (guanine, adenine, thymine and cytosine) and the additional role uracil plays in RNA. If this change were to happen, though, "uracil" would be odd base out and the article for that would need to be modified as (stated above) it also states it is one of the 4 main bases. The other option is to re-define each of the others to "one of 5 main nitrogenous bases" because there technically are 5, but when speaking of DNA, uracil is excluded. :User:Happety 14:46, 15 Dec 2003 (UTC)
See other meanings of words starting from letter:
Words begining with Cytosine:
Cytosine
Cytosine
Cytosine_arabinoside
Cytosine
{| border="1" cellpadding="2" cellspacing="0" align="right" style="margin-left:1em" ! colspan="2" align=center bgcolor="#cccccc" | Cytosine |- | IUPAC nomenclature | 4-Aminopyrimidin-2(1''H'')-one |- | Chemical formula | C4H5N3O |- | Molecular mass | 111.10 g/mol |- | Melting point | 320 - 325 °C (decomp) |- | CAS registry number | 71-30-7 |- | Simplified molecular input line entry specification | NC1=NC(NC=C1)=O |- | colspan="2" align="center" | |- |} Cytosine is one of the 5 main nucleobases used in storing and transporting genetic information within a cell in the nucleic acids DNA and RNA. It is a pyrimidine derivative, with a heterocyclic aromatic ring and two substituents attached (an amine group at position 4 and a Ketone group at position 2). The nucleoside of cytosine is cytidine. Cytosine was first discovered in 1894 when it was isolated from calf thymus tissues. A structure was proposed in 1903, and was synthesized (and thus confirmed) in the laboratory in the same year. Cytosine can be found as part of DNA, RNA, or as a part of a nucleotide. As cytosine triphosphate (CTP), it can act as a co-factor to enzymes, and can transfer a phosphate to convert adenosine diphosphate (ADP) to adenosine triphosphate (ATP). In DNA and RNA, cytosine is paired with guanine. However, it is inherently unstable, and can change into uracil (deamination). This can lead to a point mutation if not repaired by the DNA repair enzymes. Cytosine can also be methylated into 5-methylcytosine by an enzyme called DNA methyltransferase. Pyrimidines
Cytosine
Cytosine is defined here as "one of 5 main nucleobases..." As one of four bases in DNA, the other 3 (Guanine, Adenine and Thymine) are each defined as "one of 4 main nitrogenous bases..." Though it is true that in RNA, Uracil replaces Thymine, it (uracil) is also defined as "one of the 4 main nitrogenous bases..." I wonder if Cytosine should be changed to also be defined as "one of 4 main nitrogenous bases" to make it consistent with the other bases, though the article for "nitrogenous base" might need to be modified to further clarify the 4 main bases in DNA (guanine, adenine, thymine and cytosine) and the additional role uracil plays in RNA. If this change were to happen, though, "uracil" would be odd base out and the article for that would need to be modified as (stated above) it also states it is one of the 4 main bases. The other option is to re-define each of the others to "one of 5 main nitrogenous bases" because there technically are 5, but when speaking of DNA, uracil is excluded. :User:Happety 14:46, 15 Dec 2003 (UTC)
See other meanings of words starting from letter:
C
CA | CB | CD | CE | CF | CG | CH | CI | CJ | CK | CL | CM | CN | CO | CP | CR | CS | CT | CU | CW | CX | CY | CZ |Words begining with Cytosine:
Cytosine
Cytosine
Cytosine_arabinoside
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