Final answer:
Nucleotides are comprised of a nitrogenous base, a pentose sugar, and a phosphate group, while nucleosides consist only of a nitrogenous base and a pentose sugar. Nucleotides make up the DNA and RNA structures, whereas nucleosides are precursors to nucleotides.
Step-by-step explanation:
Comparison of Nucleotides and Nucleosides
Nucleotides and nucleosides are essential components in the structure of DNA and RNA. Nucleotides consist of three main components: a nitrogenous base, a pentose (five-carbon) sugar, and a phosphate group. The nitrogenous base can either be a purine (adenine or guanine) or a pyrimidine (cytosine, thymine, or uracil). This structure allows nucleotides to serve as the building blocks of nucleic acids, with the capability to form chains through phosphate-sugar backbone connections.
In contrast, a nucleoside is a simpler molecule composed of just two components: a nitrogenous base and a pentose sugar. Lacking the phosphate group(s), nucleosides are precursors to nucleotides and cannot form the polynucleotide structures of DNA or RNA by themselves.
The distinction between these two molecules is critical for understanding genetic material and various biological processes, including protein synthesis and cellular energy transfer.