A nucleotide serves as the fundamental building block of nucleic acids. It is composed of three key components: a sugar, a phosphate group, and a nitrogenous base.

Nucleotides act as the monomers that construct nucleic acids, including DNA and RNA. Each nucleotide is made up of a sugar molecule, which can either be ribose or deoxyribose, a phosphate group, and a nitrogenous base. The nitrogenous base can belong to one of four types: adenine (A), guanine (G), cytosine (C), or thymine (T) in DNA, while in RNA, uracil (U) replaces thymine.

The assembly of a nucleotide occurs through a condensation reaction where a sugar molecule and a phosphate group combine to form a sugar-phosphate backbone. Following this, the nitrogenous base attaches to the sugar, resulting in a complete nucleotide. This process is facilitated by enzymes known as nucleotidyltransferases.

Nucleotides are crucial for storing and transmitting genetic information in living organisms. In DNA, the sequence of nucleotides encodes the genetic information, which dictates the traits and characteristics of an organism. In RNA, nucleotides play a vital role in protein synthesis, where they transport genetic information from DNA to the ribosome, the site of protein production.

In conclusion, nucleotides are the essential building blocks of nucleic acids, consisting of a sugar, a phosphate group, and a nitrogenous base. They are synthesized through a condensation reaction and are indispensable for the storage and transmission of genetic information in living organisms.