Nucleosides are the structural subunit of nucleic acids such as DNA and RNA. A nucleoside is composed of a nitrogenous base covalently attached to a five-carbon sugar (ribose or deoxyribose) and is either a pyrimidine (cytosine, thymine, or uracil) or a purine (adenine or guanine). Nucleosides are responsible for encoding, transmitting, and expressing genetic information in all living things. Nucleosides play an essential role in intermediary metabolism, biosynthesis of macromolecules, and cell signaling through interaction with purinergic receptors. Thermo Fisher Scientific offers a broad range of nucleic acids and related products for research use.
Nucleotides are the building blocks of DNA and RNA. A nucleotide is composed of a nitrogenous base, a five-carbon sugar (ribose or deoxyribose), and at least one phosphate group. Thus, a nucleoside plus a phosphate group yields a nucleotide. The components used in de novo nucleotide synthesis are derived from biosynthetic precursors of carbohydrate and amino acid metabolism, and from ammonia and carbon dioxide. Nucleoside triphosphates (ATP, GTP, CTP, and UTP), play a central role in cell metabolism.