AAT Bioquest

What are the differences between ADP and ATP?

Posted August 9, 2022


ADP and ATP are molecules that contain stored chemical energy to be used by the cells. Despite this common function, there are a few notable differences between the two in terms of their physical properties as well as their biochemical roles in the human body. 

Basis for comparisonADPATP
Full NameAdenosine Di PhosphateAdenosine Tri Phosphate 
Number of phosphate groupsContains 2 phosphate groupsContains 3 terminal phosphate groups
Cehmical formulaC10H15N5O10P2C10H16N5O13P3
Chemical compositionComposed of 1 adenine molecule, a ribose sugar and two phosphate groupsComposed of 1 adenine molecule, a ribose sugar and three phosphate groups
Method of generationGenerated as a result of de-phosphorylation of ATP molecule by enzymes known as ATPasesGenerated as a result of photophosphorylation, aerobic respiration, and fermentation in biological systems
Energy state of moleculeIs the lower-energy molecule of the two because of the absence of the high-energy pyrophosphate bond Is the higher-energy molecule of the two because of the presence of the pyrophosphate bond- a high-energy bond between the last two phosphates
Molar mass427.201 g/mol507.18 g/mol
Energy releasing mechanismADP + H2O → AMP + PPi  ATP + H2O → ADP + Pi  
  • Crucial to the flow of energy in living beings
  • Plays a role in catabolic pathways such as citric acid cycle, oxidative phosphorylation, and glycolysis
  • Activation of blood platelets to initiate healing of a broken blood vessel
  • Plays a key role in mitochondrial ATP synthase complex
  • Main energy carrier molecule in living beings
  • Metabolism in cells
  • Active transportation of molecules
  • Plays a role in cell signaling
  • Activation of amino acid
  • Helps maintain cell structure
  • Synthesis of macromolecules such as DNA, RNA, and proteins
Additional resources

Physiology, Adenosine Triphosphate

PhosphoWorks™ Luminometric ATP Assay Kit *Steady Glow*

PhosphoWorks™ Fluorimetric ADP Assay Kit *Red Fluorescence*

Cell Viability Assays