ATP use

• ATP is broken down into ADP (adenosine diphosphate) and Pi (inorganic phosphate) via a hydrolysis reaction
• a phosphate bond is broken and energy is released
• ATP breakdown is catalysed by enzyme ATP hydrolase
• ATP hydrolysis can be 'coupled' to other energy-requiring reactions in the cell - the energy released being used directly to make that reaction happen
• released inorganic phosphate can be added to another compound (phosphorylation) which makes the compound more reactive
• ATP can be re-synthesised in a condensation reaction between ADP and Pi, which takes place during respiration and photosynthesis and is catalysed by enzyme ATP synthase