Nucleotides are organic molecules that serve as the monomers, or subunits, of the nucleic acids DNA (deoxyribonucleic acid) and RNA (ribonucleic acid), both of which are essential biomolecules in all life-forms on Earth. Nucleotides are the building blocks of nucleic acids; they are composed of a nitrogenous base, a five-carbon sugar (ribose or deoxyribose), and at least one phosphate group. They are also known as phosphate nucleotides.
A nucleoside is a nitrogenuous base and a 5-carbon sugar. Thus a nucleoside plus a phosphate group yields a nucleotide.
Nucleotides also function to carry packets of energy within the cell in the form of the nucleoside triphosphates (ATP, GTP, CTP and UTP), playing a central role in metabolism. In addition, nucleotides participate in cell signaling (cGMP and cAMP), and are incorporated into important cofactors of enzymatic reactions (e.g. coenzyme A, FAD, FMN, NAD, and NADP+).
In experimental biochemistry, nucleotides can be radiolabeled with radionuclides to yield radionucleotides....LESS