The subunit or monomer of the DNA structure is called a nucleotide. Nucleotides are the building blocks of DNA, and each one is composed of three essential parts:
- Pentose Sugar: This is a five-carbon sugar molecule. In the case of DNA, the sugar is deoxyribose, which is similar to ribose but lacks one oxygen atom.
- Phosphate Group: Attached to the sugar is a phosphate group, which consists of one phosphorus atom bonded to four oxygen atoms. This phosphate group is crucial for linking nucleotides together, forming the DNA backbone.
- Nitrogenous Base: Each nucleotide contains a nitrogenous base, which can be one of four types: adenine (A), thymine (T), cytosine (C), or guanine (G). These bases are responsible for encoding genetic information and pairing with complementary bases on the opposite strand of the DNA double helix.
Together, these three components form a nucleotide, which links with others to create the long, double-stranded structure of DNA essential for storing and transmitting genetic information.