ATP( Adenosine triphosphate )
ATP is the energy currency for most cellular processes. The energy released during the process of respiration is used to make an ATP molecule from ADP ( Adenosine diphosphate ) and inorganic phosphate.
ADP + Pi + 2H+ (out) ⇌ ATP + H2O + 2H+ (in)
Endothermic processes in the cell then use this ATP to drive the reactions. When the terminal phosphate linkage in ATP is broken using water, the energy equivalent to 30.5 kJ/mol is released.
Think of how a battery can provide energy for many different kinds of uses. It can be used to obtain mechanical energy, light energy, electrical energy and so on. Similarly,
ATP can be used in the cells for the contraction of muscles, protein synthesis, conduction of nervous impulses and many other activities.