Overview#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.
Nucleotide base pairs:
- Adenine (A) is always paired with thymine (T)
- Guanine (G) is always paired with cytosine (C).
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.