Adenosine 5'-triphosphate (ATP)

Adenosine 5'-triphosphate (ATP) is a multifunctional nucleotide that is most important as a "molecular currency" of intracellular energy transfer. In this role ATP transports chemical energy within cells for metabolism. It is produced as an energy source during the processes of photosynthesis and cellular respiration and consumed by many enzymes and a multitude of cellular processes including biosynthetic reactions, motility and cell division. ATP is also incorporated into nucleic acids by polymerases in the processes of DNA replication and transcription. In signal transduction pathways, ATP is used as a substrate by kinases that phosphorylate proteins and lipids, as well as by adenylate cyclase, which uses ATP to produce the second messenger molecule cyclic AMP.

The structure of this molecule consists of a purine base (adenine) attached to the 1' carbon atom of a pentose (ribose). Three phosphate groups are attached at the 5' carbon atom of the pentose sugar. When ATP is used in DNA synthesis, the ribose sugar is first converted to deoxyribose by ribonucleotide reductase. ATP was discovered in 1929 by Karl Lohmann,[1] and was proposed to be the main energy-transfer molecule in the cell by Fritz Albert Lipmann in 1941.

They like to talk about this in all the biology classes.