Final answer:
Nucleosides are composed of a nitrogenous base and pentose sugar, while nucleotides are compounds with phosphate groups, pentose sugar, and a nitrogenous base. Nucleotides are the building blocks of nucleic acids and play vital roles in genetic information storage.
Step-by-step explanation:
A nucleoside is composed of two components—(a) nitrogenous base and (b) five-carbon sugar (pentose). The nitrogenous bases are derivatives of two parent heterocyclic compounds, i.e., purine and pyrimidine. Nucleotides, on the other hand, are compounds with three building blocks: one or more phosphate groups, a pentose sugar, and a nitrogen-containing base. Nucleotides are the building blocks of nucleic acids, such as DNA and RNA, and play important roles in cell function and genetic information storage.