Nucleotides are the monomers that make up nucleic acids, which are essential for storing and transmitting genetic information. These molecules form the backbone of DNA and RNA, the blueprints for cellular functions and heredity.
Each nucleotide comprises:
- a sugar molecule (ribose in RNA and deoxyribose in DNA),
- a phosphate group,
- and a nitrogenous base.
The nitrogenous bases come in five varieties: adenine (A), guanine (G), cytosine (C), thymine (T), and uracil (U).
DNA utilizes A, G, C, and T, and is known for its double helix structure, while RNA contains A, G, C, and U and usually exists as a single strand.
- These bases pair to form the "steps" of the nucleic acid "ladder": A with T (or U in RNA), and C with G.
- Nucleotides are not just passive carriers of genetic code, but also play roles in cellular energy transfer (like ATP) and signal transduction (like cyclic AMP).
Grasping the structure of nucleotides is essential for understanding molecular biology and genetics.