Nitrogenous Bases in Nucleotide and Nucleoside
These are the nitrogen-containing heterocyclic biological compounds that become the hereditary material’s basic structure (DNA or RNA). On the basis of the cyclic structure, they contain these compounds could be divided into broad categories.
- Purins are the heterocyclic N-containing compounds comprising two heterocyclic structures (pyrimidine ring fused with imidazole ring)—the general chemical formula for a typical purine ring structure in C5H4N4. Examples of purine: Adenine, Guanine, Inosine, and Intermediate purines(Hypoxanthine, Xanthine).
|
Purine nitrogenous base |
Function |
|
Adenine |
Adenine is known to be found in DNA as well as in RNA, base pairs by the formation of two hydrogen bonds with Thymine in DNA and Uracil in RNA. |
|
Guanine |
Guanine is known to be found in DNA and RNA, base pairs by forming three hydrogen bonds with Cytosine in both DNA and RNA. |
|
Inosine |
Inosine is known to be found very specifically in the tRNA anti-codon arm and bases with all nitrogenous bases i.e., Adenine, cytosine, and uracil, except guanine. |
- Pyrimidines are heterocyclic N-containing compounds comprised of a single heterocyclic ring i.e., a pyrimidine ring—the general chemical formula for a typical pyrimidine ring structure is C5H5N. Examples of pyrimidine: Thymine, Uracil, and Cytosine.
| Pyramidine nitrogenous base | Function |
|
Thymine |
Thymine is known to be found in DNA and base pairs by the formation of two hydrogen bonds with Adenine. |
|
Uracil |
Uracil is known to be found in RNA and base pairs by the formation of two hydrogen bonds with Adenine. |
|
Cytosine |
Cytosine is known to be found in DNA as well as RNA and base pairs by the formation of three hydrogen bonds with Guanine. |
Difference Between Nucleotide and Nucleoside
Difference Between Nucleotide and Nucleoside: Nucleotides and nucleosides are nitrogenous bases with ribose sugar attached through a glycosidic bond. Therefore, a nucleoside is a nitrogenous base with ribose sugar attached through an β-glycosidic bond. In contrast, a nucleotide is a nucleoside with a phosphate group attached to ribose sugar through a phosphodiester bond.