Final answer:
Nucleosides are composed of a nitrogenous base and a five-carbon sugar. They are fundamental building blocks in biochemistry and have various applications in biology and pharmaceuticals. Modifications to nucleosides have led to the development of new nucleoside analogues.
Step-by-step explanation:
Nucleosides are composed of two components: a nitrogenous base and a five-carbon sugar (pentose). The nitrogenous bases are derivatives of two parent heterocyclic compounds, purine and pyrimidine. Nucleosides are important biomolecules and are present in all living organisms and viruses. They serve as building blocks of genetic material and have various applications in biochemistry, biology, and pharmaceuticals. Modifications to the natural nucleoside structures have led to the development of new nucleoside analogues with diverse properties and utilities.