Adenosine triphosphate (ATP) is a molecule that serves as the primary energy carrier in all living cells. It is often called the "molecular unit of currency" for intracellular energy transfer because it provides energy to drive many essential cellular processes such as muscle contraction, nerve impulse propagation, and chemical synthesis
. Structurally, ATP is a nucleoside triphosphate composed of three main parts:
- A nitrogenous base called adenine
- A sugar molecule called ribose
- A chain of three phosphate groups attached to the ribose
The energy stored in ATP is contained in the bonds between its phosphate groups, especially the bond between the second and third phosphate. When ATP is hydrolyzed (a phosphate group is removed by adding water), it releases energy and is converted into adenosine diphosphate (ADP) or adenosine monophosphate (AMP)
. Cells continuously regenerate ATP from ADP and phosphate through processes like cellular respiration, primarily in the mitochondria, to meet their energy demands. This energy is then used for tasks such as metabolic reactions, transporting substances across membranes, and mechanical work like muscle movement
. In summary, ATP is the essential energy currency of the cell, enabling life by fueling various biological functions
