EnergyTransformationATP Hydrolysis & CouplingATP Synthesis & RedoxThermochemistry
Types of EnergyEnergy: capacity to do workExamples:KineticElectricNuclearSoundThermalGravitationalChemical
PotentialEnergy Energy that matter possesses becauseof its location or structure Applied to many types of energy Exampl...
EnergyThe greater the bondenergy, the morechemically stable thebond.Bond stability is notrelated to chemicalreactivity.B...
ThermodynamicsThermodynamics: study of energytransformationsSystem: the matter under studySurroundings: everything outs...
First Law of ThermodynamicsThe total amount of energy in the universe isconstant.Thus energy cannot be created or destro...
Energy Transformation ExampleExample: Climbing a slide &sliding downConverting kinetic energy topotential energy back to...
Energy Transformation Answer: From potentialenergy in food eaten earlierthat was stored in the body Cellular respiration...
Energy Transformation Q: Where did the chemical energy in food come from? A: From light energy by plants during photosyn...
Energy Transformation Sunlight provides a dailysource of free energy for thephotosynthetic organisms. Plants transform l...
Energy TransformationThe quantity of energyis constant, but thequality is not.Organisms take inorganized energy likeligh...
Second Law of ThermodynamicsEnergy transformation make the universe moredisordered.Example: C6H12O6 + O2  CO2 + H2O + en...
HeatEnergy of random molecular motion; energy in itsmost random stateMuch of the increased entropy of universe takesthe ...
Gibbs Free EnergyThe energy that is able to perform workΔG = Gfinal – Ginitial = Gproducts - GreactantsCopyright © 2002 ...
Exergonic EndergonicGibbs Free EnergyCharacteristics Exergonic EndergonicEnergy Released AbsorbedΔG Negative PositiveReact...
Cellular EnergyEnergy transfer in a cell depends on bond energyAll chemical reactions break and form bonds:Breaking bon...
Cellular EnergyCharacteristics Exergonic EndergonicEnergy Released AbsorbedΔG Negative PositiveReaction Spontaneous Nonspo...
Cellular Energy Cellular respiration: C6H12O6 + O2  CO2 + H2O + energy Photosynthesis: CO2 + H2O + energy  C6H12O6 + O...
Equilibrium A system at equilibrium is at maximum stability. Equilibrium reactions convert back and forth with minimalen...
EquilibriumReactions in closed systems eventually reachequilibrium and can do no work.Copyright © 2002 Pearson Education,...
EquilibriumCells are open systems which maintainsdisequilibriumA cell that has reached metabolic equilibrium hasa ΔG = 0...
Adenosine Triphosphate (ATP)In most cases, the immediate source of energythat powers cellular work is ATPCopyright © 2002...
ATP HydrolysisHydrolysis releases the end phosphate group:ATP  ADP + PiΔG is -7.3 kcal/mol under standard conditionsΔG...
Phosphate BondsReferred to as high-energy phosphate bonds butare actually fairly weak covalent bondsEach of the three ph...
CouplingEnergy from thehydrolysis of ATP iscoupled toendergonic processesby transferring thephosphate group toanother mol...
Types of Cellular Work Transport work pumping substances acrossmembranes against the direction ofspontaneous movement M...
ATP Coupling and workFigure 9.2
ATP CouplingATP hydrolysis does not occur on its own.Process is carried out with enzymes that can transferthe phosphate
ATP SynthesisATP is continually regenerated by adding aphosphate group to ADPIn a working muscle cell the entire pool of...
ATP SynthesisRegeneration of ATP is an endergonic process:investment of energy: ΔG = +7.3 kcal/molEnergy for renewal co...
Methods of ATP SynthesisSubstrate-level phosphorylationOxidative phosphorylation
Substrate-level PhosphorylationDirect method of ATP synthesisFood
Substrate-level Phosphorylation An enzyme transfers phosphatefrom substrate to ADP Example from glycolysis incellular re...
Oxidative PhosphorylationIndirect method of ATP synthesisUses redox reactions where electrons aretransferred to an inter...
Redox Reactionsreactions involving electron transfer
The Principle of Redox Oxidation A substance loses electrons Is oxidized Reduction A substance gains electrons Is re...
Redox ReactionsReducing Agent:substance that LOSES electronscauses the other substance to be reducedOxidizing Agent:s...
Examples of Redox ReactionsNa + Cl Na++ Cl–becomes oxidized(loses electron)becomes reduced(gains electron)Xē + Y X + Yēbec...
Redox and ElectronegativitySome redox reactionsdo not completelyexchange electronsChange the degree ofelectron sharing i...
Redox in Cellular RespirationOxidation ofmethane is the maincombustion reactionthat occurs at theburner of a gas stoveRe...
Redox in Cellular RespirationGlucose is oxidized and oxygen is reducedOrganic molecules are excellent fuels becausetheir...
Oxidizing Agent in MetabolismNAD+Nicotinamide adenine dinucleotidea coenzymeaccept electrons from organiccompounds for...
Redox with NAD+/NADHNAD ++ e- NADH (electron carrier)
NAD+HOOO O–OO O–OOOPPCH2CH2HO OHHHHO OHHOHHN+C NH2HNHNH2NNNicotinamide(oxidized form)NH2+ 2[H](from food)DehydrogenaseRedu...
Oxidative PhosphorylationIndirect method of ATP SynthesisFood  NADH  ATP  WorkNADHFoodElectrontransport chainNAD+Redu...
Reducing Agent in MetabolismEach NADH molecule represents stored energythat can make ATPWhen electrons in NADH fall down...
Redox in the CellMany metabolic processes consist of chains ofredox reactions.A-AB-BC-C DD-
Harnessing Free EnergyWholesale releaseof energy from fuelis difficult toharness efficientlyfor workExample: explosionof...
Harnessing Free EnergyCells release free energy by gradually breakingdown organic fuel in a series of reactions eachcatal...
Electron Transport Chain (ETC)Consists of a number ofproteins that aid withthe transfer ofelectrons, thuscontrolling the ...
If electron transfer is not stepwise…A large release of energy occursExample: Oxidation of sugarhttp://www.youtube.com/w...
Food & Activation EnergyMain energy foods are reservoirs of electronsassociated with hydrogenActivation energy is the ba...
Demo: Food & Activation EnergySupply activation energy to glucose by igniting itReleases 686 kcal of heat per mole
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Thermochemistry

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  • Q: Given single and double bonds, which do you suppose requires more energy to break?
  • Q: How much work energy is available in a reaction in equilibrium? - 0
  • Q: What happens to the energy? - it needs to be focused
  • Q: What reaction do you know of that would be classified as redox? - NaCl
  • Thermochemistry

    1. 1. EnergyTransformationATP Hydrolysis & CouplingATP Synthesis & RedoxThermochemistry
    2. 2. Types of EnergyEnergy: capacity to do workExamples:KineticElectricNuclearSoundThermalGravitationalChemical
    3. 3. PotentialEnergy Energy that matter possesses becauseof its location or structure Applied to many types of energy Example: gravitational potential energy Biological importance: Chemical energy is a form of potentialenergy in molecules because of thearrangement of atomshttp://25.media.tumblr.com/d00efeba5498fca950517622e4bad651/tumblr_mkmgtfqDYF1rj73y8o1_500.jpg
    4. 4. EnergyThe greater the bondenergy, the morechemically stable thebond.Bond stability is notrelated to chemicalreactivity.Bond Type Average BondEnergy (kJ/mol)H-H 436C-H 411O-H 459N-H 391C-C 346C-O 359C=O 799O=O 494
    5. 5. ThermodynamicsThermodynamics: study of energytransformationsSystem: the matter under studySurroundings: everything outside the systemClosed system: isolated from its surroundingsOpen system: energy (and often matter) can betransferred between the system andsurroundingsExample: Organisms absorb energy in organicmolecules and release heat and metabolic wasteproducts
    6. 6. First Law of ThermodynamicsThe total amount of energy in the universe isconstant.Thus energy cannot be created or destroyed.Energy can be transferred and transformed,converting from one form to another
    7. 7. Energy Transformation ExampleExample: Climbing a slide &sliding downConverting kinetic energy topotential energy back to kineticenergyQuestion: Where did the initialkinetic energy for climbingcome from?Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
    8. 8. Energy Transformation Answer: From potentialenergy in food eaten earlierthat was stored in the body Cellular respiration unleashesthe potential energy in thefoods that we consumehttp://intentblog.com/wp-content/uploads/2013/03/url-19.jpeg
    9. 9. Energy Transformation Q: Where did the chemical energy in food come from? A: From light energy by plants during photosynthesishttp://media.salon.com/2010/08/the_quiet_vegetarian.jpg
    10. 10. Energy Transformation Sunlight provides a dailysource of free energy for thephotosynthetic organisms. Plants transform light tochemical energy; they do notproduce energy. Nonphotosyntheticorganisms depend on atransfer of free energy fromphotosynthetic organisms inthe form of organicmolecules.Light energyECOSYSTEMCO2 + H2OPhotosynthesisin chloroplastsCellular respirationin mitochondriaOrganicmolecules+ O2ATPpowers most cellular workHeatenergyFigure 9.1
    11. 11. Energy TransformationThe quantity of energyis constant, but thequality is not.Organisms take inorganized energy likelight or organicmolecules and replacethem with less orderedforms, especially heat.Light energyECOSYSTEMCO2 + H2OPhotosynthesisin chloroplastsCellular respirationin mitochondriaOrganicmolecules+ O2ATPpowers most cellular workHeatenergyFigure 9.1
    12. 12. Second Law of ThermodynamicsEnergy transformation make the universe moredisordered.Example: C6H12O6 + O2  CO2 + H2O + energyEntropy: a measure of disorder, chaos, orrandomnessAlthough order can increase locally in a particularsystem, it requires the input of energy and theuniverse will still trend towards randomization.Example: CO2 + H2O + energy  C6H12O6 + O2
    13. 13. HeatEnergy of random molecular motion; energy in itsmost random stateMuch of the increased entropy of universe takesthe form of increasing heatLiving cells unavoidably convert organized forms ofenergy to heat.The metabolic breakdown of food ultimately isreleased as heat even if some of it is divertedtemporarily to perform work for the organism.
    14. 14. Gibbs Free EnergyThe energy that is able to perform workΔG = Gfinal – Ginitial = Gproducts - GreactantsCopyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
    15. 15. Exergonic EndergonicGibbs Free EnergyCharacteristics Exergonic EndergonicEnergy Released AbsorbedΔG Negative PositiveReaction Spontaneous NonspontaneousProducts More stabile, less energy Less stable, more energyCopyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
    16. 16. Cellular EnergyEnergy transfer in a cell depends on bond energyAll chemical reactions break and form bonds:Breaking bonds require energyForming bonds releases energyThe net energetic effect of the reaction:Exergonic when energy for breaking bonds is lessthan formingEndergonic when energy for breaking bonds is morethan forming
    17. 17. Cellular EnergyCharacteristics Exergonic EndergonicEnergy Released AbsorbedΔG Negative PositiveReaction Spontaneous NonspontaneousProductsMore stabileLess energyLess stableMore energyBond energy Breaking < forming Breaking > forming
    18. 18. Cellular Energy Cellular respiration: C6H12O6 + O2  CO2 + H2O + energy Photosynthesis: CO2 + H2O + energy  C6H12O6 + O2Example Cellular Respiration PhotosynthesisEnergy Released AbsorbedΔG-2870 kJ/mol-686 kcal/mol+2870 kJ/mol+686 kcal/molReaction Spontaneous NonspontaneousClassification Exergonic Endergonic
    19. 19. Equilibrium A system at equilibrium is at maximum stability. Equilibrium reactions convert back and forth with minimalenergy. ΔG = 0 Example: In a chemical reaction, the rate of forward andbackward reactions are equal. There is no change in theconcentration of products or reactants.
    20. 20. EquilibriumReactions in closed systems eventually reachequilibrium and can do no work.Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
    21. 21. EquilibriumCells are open systems which maintainsdisequilibriumA cell that has reached metabolic equilibrium hasa ΔG = 0 and is dead!Metabolic disequilibrium is one of the definingfeatures of lifeCopyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
    22. 22. Adenosine Triphosphate (ATP)In most cases, the immediate source of energythat powers cellular work is ATPCopyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
    23. 23. ATP HydrolysisHydrolysis releases the end phosphate group:ATP  ADP + PiΔG is -7.3 kcal/mol under standard conditionsΔG is -13 kcal/mol in a cellCopyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
    24. 24. Phosphate BondsReferred to as high-energy phosphate bonds butare actually fairly weak covalent bondsEach of the three phosphate groups has a negativechargeTheir repulsion contributes to the instability of thisregion of the ATP molecule.Their hydrolysis yields energy as the products aremore stable
    25. 25. CouplingEnergy from thehydrolysis of ATP iscoupled toendergonic processesby transferring thephosphate group toanother molecule.The phosphorylatedmolecule is now morereactive.Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
    26. 26. Types of Cellular Work Transport work pumping substances acrossmembranes against the direction ofspontaneous movement Mechanical work beating of cilia contraction of muscle cells movement of chromosomes Chemical work driving endergonic reactions such asthe synthesis of polymers frommonomersFig 9.2
    27. 27. ATP Coupling and workFigure 9.2
    28. 28. ATP CouplingATP hydrolysis does not occur on its own.Process is carried out with enzymes that can transferthe phosphate
    29. 29. ATP SynthesisATP is continually regenerated by adding aphosphate group to ADPIn a working muscle cell the entire pool of ATP isrecycled once each minuteOver 10 million ATP consumed and regenerated persecond per cellCopyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
    30. 30. ATP SynthesisRegeneration of ATP is an endergonic process:investment of energy: ΔG = +7.3 kcal/molEnergy for renewal comes from catabolicreactions in the cellRelocation of electrons in organic compoundsreleases chemical potential energy to drivesynthesis of ATPCopyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
    31. 31. Methods of ATP SynthesisSubstrate-level phosphorylationOxidative phosphorylation
    32. 32. Substrate-level PhosphorylationDirect method of ATP synthesisFood
    33. 33. Substrate-level Phosphorylation An enzyme transfers phosphatefrom substrate to ADP Example from glycolysis incellular respiration(Pyruvate Kinase)http://classconnection.s3.amazonaws.com/770/flashcards/403770/jpg/substrate_level_phosphorylation1311374648416.jpg
    34. 34. Oxidative PhosphorylationIndirect method of ATP synthesisUses redox reactions where electrons aretransferred to an intermediate forming highenergy molecules (NADH, FADH2)NADHFoodElectrontransport chainNAD+
    35. 35. Redox Reactionsreactions involving electron transfer
    36. 36. The Principle of Redox Oxidation A substance loses electrons Is oxidized Reduction A substance gains electrons Is reduced Loss of Electrons is Oxidation Gain of Electron is ReductionLEO the lion says GER
    37. 37. Redox ReactionsReducing Agent:substance that LOSES electronscauses the other substance to be reducedOxidizing Agent:substances that GAIN electronscauses the other substance to be oxidized
    38. 38. Examples of Redox ReactionsNa + Cl Na++ Cl–becomes oxidized(loses electron)becomes reduced(gains electron)Xē + Y X + Yēbecomes oxidizedbecomes reducedWe could generalize a redox reaction this way:X is the electron donor, is called the reducing agent, it reduces Y which accepts the donated electronY is the electron acceptor, it oxidizes X by removing its electron is the reducing agent
    39. 39. Redox and ElectronegativitySome redox reactionsdo not completelyexchange electronsChange the degree ofelectron sharing incovalent bondsAn electron losespotential energy whenit shifts from a lesselectronegative atomtoward moreelectronegative oneCH4HHHHC O O O O OCH HMethane(reducingagent)Oxygen(oxidizingagent)Carbon dioxide Water+ 2O2 CO2 + Energy + 2 H2Obecomes oxidizedbecomes reducedReactants ProductsFigure 9.3
    40. 40. Redox in Cellular RespirationOxidation ofmethane is the maincombustion reactionthat occurs at theburner of a gas stoveReplace equationwith glucose to getthe equation forcellular respirationCH4HHHHC O O O O OCH HMethane(reducingagent)Oxygen(oxidizingagent)Carbon dioxide Water+ 2O2 CO2 + Energy + 2 H2Obecomes oxidizedbecomes reducedReactants ProductsFigure 9.3
    41. 41. Redox in Cellular RespirationGlucose is oxidized and oxygen is reducedOrganic molecules are excellent fuels becausetheir hydrogens are a source of electrons with apotential to “fall” closer to oxygenC6H12O6 + 6O2 6CO2 + 6H2O + Energybecomes oxidizedbecomes reduced
    42. 42. Oxidizing Agent in MetabolismNAD+Nicotinamide adenine dinucleotidea coenzymeaccept electrons from organiccompounds forming NADHacts as an oxidizing agent
    43. 43. Redox with NAD+/NADHNAD ++ e- NADH (electron carrier)
    44. 44. NAD+HOOO O–OO O–OOOPPCH2CH2HO OHHHHO OHHOHHN+C NH2HNHNH2NNNicotinamide(oxidized form)NH2+ 2[H](from food)DehydrogenaseReduction of NAD+Oxidation of NADH2 e–+ 2 H+2 e–+ H+NADHOH HNC +Nicotinamide(reduced form)NH+H+Figure 9.4Redox with NAD+/NADH Dehydrogenase enzyme removes a pair of hydrogenatoms (2 electrons and 2protons) from the substrate (eg.sugar) 2 electrons and 1 H+ stay onnicotinamide leaving 1 H+
    45. 45. Oxidative PhosphorylationIndirect method of ATP SynthesisFood  NADH  ATP  WorkNADHFoodElectrontransport chainNAD+Reduction Oxidation
    46. 46. Reducing Agent in MetabolismEach NADH molecule represents stored energythat can make ATPWhen electrons in NADH fall down an energygradient to oxygen, the exergonic reactionreleases a free energy change of – 53 kcal/molOccurs in the mitochondria through a processcalled the electron transport chain (ETC)Oxygen is the final electron acceptor
    47. 47. Redox in the CellMany metabolic processes consist of chains ofredox reactions.A-AB-BC-C DD-
    48. 48. Harnessing Free EnergyWholesale releaseof energy from fuelis difficult toharness efficientlyfor workExample: explosionof a gas tank can’tdrive a car
    49. 49. Harnessing Free EnergyCells release free energy by gradually breakingdown organic fuel in a series of reactions eachcatalyzed by an enzymeHydrogens are taken from organic fuelSome are transferred first to a coenzyme (NAD+)before going to oxygen
    50. 50. Electron Transport Chain (ETC)Consists of a number ofproteins that aid withthe transfer ofelectrons, thuscontrolling the releaseof energy for ATPsynthesisCopyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings2 H 1/2 O2(from food via NADH)2 H++ 2 e–2 H+2 e–H2O1/2 O2Controlledrelease ofenergy forsynthesis ofATPATPATPATPElectrontransportchainFreeenergy,G+Figure 9.5 BOrganic fuel NADH ETC Oxygen→ → →
    51. 51. If electron transfer is not stepwise…A large release of energy occursExample: Oxidation of sugarhttp://www.youtube.com/watch?v=K8DRM3k39Pghttp://www.youtube.com/watch?v=KZq7W2cqf8Ihttp://www.youtube.com/watch?v=nN8xD_bv2aQ&feature=relatedhttp://www.youtube.com/watch?v=mamoT11TEV4&feature=relatedExample: Reaction of hydrogen andoxygen to form waterhttp://www.youtube.com/watch?v=NYC23ANpEdsUncontrolled reactionFigure 9.5 AFreeenergy,GH2OExplosiverelease ofheat and lightenergyH2 + 1/2 O2
    52. 52. Food & Activation EnergyMain energy foods are reservoirs of electronsassociated with hydrogenActivation energy is the barrier that preventselectrons from falling to a lower energy stateWithout it, food substances would combinespontaneously with oxygen
    53. 53. Demo: Food & Activation EnergySupply activation energy to glucose by igniting itReleases 686 kcal of heat per mole

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