Nucleotide are organic molecules that serve as the monomer units for forming the nucleic acid polymers Deoxyribonucleic Acid (DNA) and Ribonucleic Acid (RNA), both of which are essential biomolecules within all life-forms on Earth.

Nucleotide are the building blocks of nucleic acids; they are composed of three subunit molecules:

  • a nitrogenous base (also known as nucleobase or ACGT)
    • adenine (A)
    • thymine (T)
    • guanine (G)
    • uracil (U)
    • cytosine (C).
  • a five-carbon sugar (ribose or deoxyribose)
  • at least one phosphate group.

The nitrogenous bases form hydrogen bonds between opposing DNA strands to form the rungs of the "twisted ladder" or double helix of DNA or a biological catalyst that is found in the Nucleotides.

Nucleotide base pairs:

  • Adenine (A) is always paired with thymine (T)
  • Guanine (G) is always paired with cytosine (C).
Adenine (A) forms two hydrogen bonds with thymine in DNA and two hydrogen bonds with uracil in RNA, while three hydrogen bonds are formed between guanine and cytosine. There are a variety of other non-canonical base pairs that occur in nature due to the versatility of these molecular structures.

Uracil is only present in RNA, replacing thymine.

Pyrimidines include thymine, cytosine, and uracil. They have a single ring structure.

Purines include adenine and guanine. They have a double ring structure.

More Information#

There might be more information for this subject on one of the following: