Categories: BIOCHEMISTRY

What is Difference between Nucleotide and Nucleoside?

Difference between Nucleotide and Nucleoside is that Living beings that are made up of a single cell also perform all the activities of life, such as nutrition, reproduction, and relations with the external world. They are organisms like the others, although unicellular, where a single cell is the one that carries out all these functions. To the second group of organisms, consisting of many cells where multicellular beings are generated.

Nucleosides

Nucleosides, are organic monomeric molecules, are the precursors of nucleotides: deoxyribonucleic acid (DNA) and ribonucleic acid (RNA). Nucleosides are composed of two parts: a heterocyclic amine, called a nitrogen base and a sugar molecule; The sugar molecule is ribose or deoxyribose. When a phosphate group is linked to a nucleoside, then it is transformed into a nucleotide.

That said, nucleosides are made up of the junction of a pentose and a nitrogenous base. This union is always carried out in the same way, since a glycosidic bond is made between the carbon of the pentose and the nitrogen of the pubic bases or that of the pyramidic bases. If the deoxyribose is the pentose present, then the nucleoside is named with the prefix ‘deoxy’. From the nucleic acids, for example, adenosine, uridine, cytidine, deoxyadenosine, deoxyguanosine, deoxythymidine and deoxycytidine can be obtained. Thus, depending on the pentose they contain, they can be called ‘Deoxyribonucleosides’ (the pentose is 2-deoxyribose) and ‘Ribonucleosides’ (the pentose is ribose).

Nucleotides

Nucleotides are organic compounds that result from the union between a nucleoside and a phosphoric acid molecule. We can say that the union is a link between pentose and phosphoric acid. Therefore, the most important thing is that the bonding is carried out with the alcohol group of carbon 4 of the pentose. However, nucleotides can also be found with the phosphate group attached to carbon 2 and 3. We can divide the nucleotides into ‘Deoxyribonucleotides’ (if sugar is deoxyribose) and ‘Ribonucleotides’ (when sugar is ribose).

In this sense, nucleotides in nucleic acids (DNA and RNA) can act as monomers and can also act as free molecules. DNA is formed by guanine, thymine, adenine, and cytosine. Also, we have the RNA in which adenine, guanine, cytosine, and uracil are involved. On the other hand, the nucleotide sugar belongs to the pentoses group because they have five carbon atoms; it can be ribose or deoxyribose.

Difference between Nucleosides and Nucleotides

NUCLEOSIDE	NUCLEOTIDE
It is the monomeric molecule resulting from the union between the pentose and a nitrogenous base.	It is a monomeric compound formed by a nucleoside and a phosphate group.
DNA and RNA consist of nucleotide chains or polymers.	Nucleotides in DNA and RNA can act as monomeric and as free molecules
Nucleosides can be of two types: deoxyribonucleosides and ribonucleosides	There are two types of nucleotides: Deoxyribonucleotides and Ribonucleotides.