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Published byAmberlynn Avice Strickland Modified over 9 years ago
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ATP – Cellular Energy Organisms/cells are endergonic systems must have energy for Mechanical work Transport work Chemical work Ribose, Adenine, 3 phosphates
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ATP – Cellular Energy Adenosine tri phosphate 3 phosphate groups covalently bonded Can be removed by hydrolysis High energy bonds Negative phosphates repel one another, easy to remove Compressed spring analogy Hydrolysis --- G = -7.3 kcal/mol Exergonic Spontaneous Free energy | V Instability of its P bonds makes ATP an excellent energy donor
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ATP = Energy…. How? Work of life is done by energy coupling use exergonic (catabolic) reactions to fuel endergonic (anabolic) reactions ++ energy + + digestionsynthesis
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ATP – Energy Coupling
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How does ATP transfer energy? P O–O– O–O– O –O–O P O–O– O–O– O –O–O P O–O– O–O– O –O–O 7.3 energy + P O–O– O–O– O –O–O ATP → ADP releases energy ∆G = -7.3 kcal/mole Fuel other reactions Phosphorylation released P i can transfer to other molecules destabilizing the other molecules enzyme that phosphorylates = “kinase” ADPATP
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An example of Phosphorylation… Building polymers from monomers need to destabilize the monomers phosphorylate! C H OH H HOHO C C H O H C + H2OH2O + +4.2 kcal/mol C H OH C H P + ATP + ADP H HOHO C + C H O H CC H P + PiPi “kinase” enzyme -7.3 kcal/mol -3.1 kcal/mol enzyme H OH C H HOHO C synthesis
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ATP – Drives Cellular Work Phosphorylation makes molecule less stable, more likely to react Conformational change Conformational Change Increased Reactivity ATP is replenished in cellular respiration ADP + Pi ATP
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Cells can’t store ATP good energy donor, not good energy storage too reactive transfers P i too easily carbohydrates & fats are long term energy storage ATP / ADP cycle A working muscle recycles over 10 million ATPs per second ATP ADP PiPi + 7.3 kcal/mole cellular respiration
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