Difference Between ADP and ATP

Main Difference – ADP vs ATP

ATP and ADP are molecules containing a great amount of stored chemical energy. The Adenosine group of ADP and ATP is composed of Adenine although they also contain phosphate groups. Chemically, ATP stands for Adenosine Tri Phosphate and ADP stands for Adenosine Di Phosphate. The third phosphate of ATP is attached to the other two phosphate groups with a very high energy bond, and a large amount of energy is released when that phosphate bond is broken. ADP results in the removal of the third phosphate group from ATP. This is the key difference between ATP and ADP. However, compared to ATP, ADP molecule has much less chemical energy, because the high-energy bond between the last 2 phosphates has been broken. Based on the molecular structure of ATP and ADP, they have their own of ADP. In this article, let’s elaborate what are the differences between ATP and ADP.Difference Between ADP and ATP - infographic

What is Adenosine Tri Phosphate (ATP)

Adenosine triphosphate (ATP) is used by biological creatures as a coenzyme of intracellular chemical energy transfer within cells for metabolism. In other words, it is the main energy carrier molecule used in living things. ATP is generated as a result of photophosphorylation, aerobic respiration, and fermentation in biological systems, which facilitates the accumulation of a phosphate group to an ADP molecule. It consists of adenosine, which is composed of an adenine ring and a ribose sugar and three phosphate groups also known as triphosphate. Biosynthesis of ADP as a result of,

1. Glycolysis

Glucose + 2NAD+ + 2 Pi + 2 ADP = 2 pyruvate + 2 ATP + 2 NADH + 2 H2O

2. Fermentation

Glucose = 2CH3CH(OH)COOH + 2 ATPDifference Between ADP and ATP

What is Adenosine Di Phosphate (ADP)

ADP consists of adenosine which is composed of an adenine ring and a ribose sugar and two phosphate groups also known as diphosphate. This is vital to the flow of energy in biological systems. It is generated as a result of de-phosphorylation of ATP molecule by enzymes known as ATPases. The breakdown of a phosphate group from ATP results in the release of energy to metabolic reactions. IUPAC name of ADP is [(2R,3S,4R,5R)-5-(6-aminopurin-9-yl)-3,4-dihydroxyoxolan-2-yl]methyl phosphono hydrogen phosphate. ADP is also known as adenosine 5′-diphosphate.Main Difference - ADP vs ATP

Difference Between ADP and ATP

ATP and ADP may have significantly different physical and functional characteristics. These can be categorized into following subgroups,

Abbreviation

ATP: Adenosine Triphosphate

ADP: Adenosine Di Phosphate

Molecular Structure

ATP: ATP consists of adenosine (an adenine ring and a ribose sugar) and three phosphate groups (triphosphate).Difference Between ADP and ATP-3

ADP: ADP consists of adenosine (an adenine ring and a ribose sugar) and two phosphate groups.

Difference Between ADP and ATP - ADP

Number of Phosphates Groups

ATP: ATP has three phosphate groups.

ADP: ADP has two phosphate groups.

Chemical Formula

ATP: Its chemical formula is C10H16N5O13P3.

ADP: Its chemical formula is C10H15N5O10P2.

Molar Mass

ATP: The molar mass is 507.18 g/mol.

ADP: The molar mass is 427.201 g/mol.

Density

ATP: The density of ATP is  1.04 g/cm3.

ADP: The density of ADP is 2.49 g/mL.

Energy State of Molecule

ATP: ATP is a high-energy molecule compared to ADP.

ADP: ADP is a low energy molecule compared to ATP.

Energy Releasing Mechanism

ATP: ATP + H2O → ADP + Pi   ΔG˚ = −30.5 kJ/mol (−7.3 kcal/mol)

ADP: ADP + H2O → AMP + PPi  

Functions in Biological System

ATP:

  • Metabolism in cells
  • Amino acid activation
  • Synthesis of macromolecules such as DNA, RNA, and protein
  • Active transport of molecules
  • Maintaining cell structure
  • Contribute to cell signalling

ADP:

  • Catabolic pathways such as glycolysis, citric acid cycle and oxidative phosphorylation
  • Blood platelet activation
  • Play a role in mitochondrial ATP synthase complex

In conclusion, ATP and ADP molecules are types of “universal power source” and the key difference between them is the number of phosphate group and energy content. As a result, they may have substantially different physical properties and different biochemical roles in the human body. Both ATP and ADP are involved in the important biochemical reactions in the human body and thus they are considered as vital biological molecules.

References:

Voet D, Voet JG (2004). Biochemistry 1 (3rd ed.). Hoboken, NJ.: Wiley. ISBN 978-0-471-19350-0.

Ronnett G, Kim E, Landree L, Tu Y (2005). Fatty acid metabolism as a target for obesity treatment. Physiol Behav 85 (1): 25–35.

Belenky P, Bogan KL, Brenner C (January 2007). NAD+ metabolism in health and disease. Trends Biochem. Sci. 32 (1): 12–9.

Jensen TE, Richter EA (2012). Regulation of glucose and glycogen metabolism during and after exercise. J. Physiol. (Lond.) 590 (Pt 5): 1069–76.

Resetar AM, Chalovich JM (1995). Adenosine 5′-(gamma-thiotriphosphate): an ATP analog that should be used with caution in muscle contraction studies. Biochemistry 34 (49): 16039–45.

Image Courtesy:

“Adenosine-diphosphate-3D-balls” By Jynto (talk) – Own work This chemical image was created with Discovery Studio Visualizer. (CC0) via

“ATP-xtal-3D-balls” By Ben Mills – Own work (Public Domain) via  

“Adenosindiphosphat protoniert” By NEUROtiker – Own work (Public Domain) via  

“Adenosintriphosphat protonier” By NEUROtiker – Own work, (Public Domain) via

About the Author: Geesha

Geesha has a BSc (Hons) degree in Food Science and Technology and Master's degree in Food and Nutrition. She is currently reading for her PhD in Food science and technology. Sharing what she learned is a passion of hers and enjoys writing.


Related pages


piaget adaptionlanguage and dialecttime difference between est and pstaustralian constitutional monarchyaddition and condensation polymerization differencesest to pst time differencemolecular structure of cyclohexanecharging by friction conduction and inductionmalleable materials examplestax return airport sydneycolloids vs crystalloidsultimate tensile stress definitioncpi formula calculationprojectile motion numericalscatabolism vs anabolismcerita goldilocks and the three bearsthe difference between a motel and hotelprocess of oogenesis and spermatogenesiswhat is regular verb and irregular verbdiff type of kisswhat are the differences between light and electron microscopessmooched meaningsardonic humor definitionmncs and tncswhat is the difference between a colon and semicolonsatire sarcasmmnemonic poemwhat is difference between bits and byteswhat is the difference between watts and voltshow are glucose and fructose differentegg roll versus spring rollenunciate definesexual and asexual reproduction in fungidifference between lifi and wifisoil flora definitionpixies mythical creaturesdifference between peanut and groundnutcaribou and reindeer differenceslinking and helping verbcompare fet and bjtinner planets definitionsn2 vs sn1difference between plain and self raising flourexamples of internal rhymespathetic fallacy definecentromere and kinetochorespell estheticianamylose iodine testdefinition of photosystem 2classical tragedy definitiondefinition recount textmorphology in grammarwhat is the difference between negative reinforcement and punishmentwhat is the difference between verbal and nonverbal communicationamylose diagrammechanical waves vs electromagnetic wavesdefine bicameral congressundamped vibrationallylic bondheavy whipping cream and heavy cream the samewhat is the difference between kefir and yogurthunger vs appetitedefine upthrustcell cytoplasm definitiondifference between exocytosis and endocytosisantagonist and protagonistexamples of paralanguageaction or linking verbbrass and copper differencetypes of monocotswhat is the moral lesson of hansel and gretelliterary definition of parallelismfennel seed picsstarfish radial symmetrywhere does transcription occur in eukaryotesassertive sentencesnonpolar exampleswhat is the difference between a shrub and a treedifference between a semicolon and a colondifferentiate between diffusion and osmosiswhat is the difference between xylem and phloem tissue