Nucleoside: A nucleoside is formed when a pentose sugar (Ribose or De-oxy-ribose) is added with a nitrogen base (Adenine, Guanine, Thymine, Cytosine, Uracil)
Nucleoside may be of different types on the basis of sugar and bases:
- Ribose sugar + Guanine = Guanosine
- Ribose sugar + Adenine = Adenosine
- Ribose sugar + Cytosine = Cylidine
- Ribose sugar + Uracil = Uradine
When deoxyribose is the pentose sugar the nucleosides will be of the following types:
- Deoxyribose + Guanine = De-guanosine
- Deoxyribose + Adenine = De- adenosine
- Deoxyribose + Cytosine = De- cytidine
- Deoxyribose + Thymine = De-thymidine
It is clear from the above statement that both ribose and deoxyribose unite with purine bases, such as-adenine and guanine and pyrimidine base, such as- cytosine. The fourth pyrimidine base is different for both ribose and deoxyribose sugar. Ribose sugar unites with uracil but deoxyribose unites with thymine.
