Which bases are purines and which are pyrimidines?

Adenine and guanine are double-ring purines, while cytosine, thymine, and uracil are single-ring pyrimidines.

Besides building DNA and RNA, what do nucleotides do?

Nucleotides act as energy carriers such as ATP, as signaling molecules such as cyclic AMP, and as components of coenzymes such as NAD and coenzyme A.

Nucleotide Chemistry

Nucleotides are the building blocks of nucleic acids and also serve as energy carriers, signaling molecules, and coenzyme components, making their chemistry central to biochemistry.

Definition

Nucleotide chemistry is the study of the structures and reactivity of nucleotides—comprising a nitrogenous base, a pentose sugar, and one or more phosphate groups—and the bonds that link them into nucleic acids.

Scope

This topic covers the structures of purine and pyrimidine bases, nucleosides and nucleotides, the phosphodiester linkage that joins them into chains, and the many non-genetic roles of nucleotides as energy currency, second messengers, and parts of coenzymes.

Core questions

How are purine and pyrimidine bases distinguished chemically?
What is the phosphodiester bond and how does it build nucleic acid chains?
Why do nucleotides serve so many roles beyond information storage?
How does ribose differ from deoxyribose?

Key theories

Nucleotides as a chemical multitool: The same nucleotide framework that builds nucleic acids also underlies energy carriers such as ATP, signaling molecules such as cyclic AMP, and coenzymes such as NAD and FAD, reflecting the chemical versatility of the base–sugar–phosphate unit.

Mechanisms

A base bonds to the 1' carbon of a pentose to form a nucleoside; phosphorylation of the 5' hydroxyl yields a nucleotide. Polymerization proceeds through phosphodiester bonds linking the 3' hydroxyl of one sugar to the 5' phosphate of the next, giving a directional chain. The same nucleotides function in energy transfer through phosphoanhydride bonds, in signaling as cyclic nucleotides, and as redox-active coenzymes.

Clinical relevance

Nucleotide chemistry is foundational to oligonucleotide synthesis, analytical biochemistry, and the design of nucleotide-based tools in chemical biology. The treatment is descriptive and non-prescriptive.

History

Levene characterized the components of nucleotides early in the twentieth century, and Todd established the chemical synthesis and structure of nucleotides and the phosphodiester linkage, work recognized with a Nobel Prize in Chemistry.

Key figures

Phoebus Levene
Alexander Todd

Seminal works

nelson2021
voet2016

Frequently asked questions

Which bases are purines and which are pyrimidines?: Adenine and guanine are double-ring purines, while cytosine, thymine, and uracil are single-ring pyrimidines.
Besides building DNA and RNA, what do nucleotides do?: Nucleotides act as energy carriers such as ATP, as signaling molecules such as cyclic AMP, and as components of coenzymes such as NAD and coenzyme A.