Energy, ATP, and EnzymesEnergy, ATP, and Enzymes

CH. 6CH. 6

Ch. 81. Energy

1. Types, laws, conversions2. Chemical reactions

1. Endergonic, exergonic3. ATP

1. Source of energy for cells4. Enzymes

1. Speed up chemical reactions2. Lower activation energy

EnergyEnergy

Energy is...Energy is... The ability toThe ability to do workdo work The ability to The ability to transfer transfer

heatheat Forms of EnergyForms of Energy

Chemical energyChemical energy Nuclear energyNuclear energy Solar energySolar energy Heat energyHeat energy Mechanical and Mechanical and

ElectricalElectrical

Measuring EnergyMeasuring Energy Two units commonly usedTwo units commonly used::

CaloriesCalories (C): (C): Amount of energy it Amount of energy it takes to raise takes to raise one gram of water 1one gram of water 1ooCCCalories in Calories in foodfood (C) are actually (C) are actually kilocalories(kilocalories(kcalkcal) = ) = 1000 calories1000 calories

JoulesJoules (J): 4.18 Joules = 1 calorie(J): 4.18 Joules = 1 calorie

So they are actually 100,000 calorie packs!

Energy due to positionEnergy due to position - - gravitational, electrical, or in gravitational, electrical, or in chemical bonds chemical bonds (called chemical energy)(called chemical energy)

StoredStored energyenergy

Potential EnergyPotential Energy

PositionPosition: boulder at : boulder at the top of the hill, the top of the hill, water behind a dam, water behind a dam, stick of plastiquestick of plastique

ChemicalChemical: tank of : tank of gas, hamburgergas, hamburger

Potential EnergyPotential Energy

Kinetic EnergyKinetic Energy Energy due to Energy due to motion or motion or

actionaction Electromagnetic waves (light), Electromagnetic waves (light),

heat, motion, electrical currentheat, motion, electrical current

Heat and TemperatureHeat and Temperature Heat - thermal energyHeat - thermal energy = =

kinetic kinetic energy from the movement of energy from the movement of atoms or moleculesatoms or molecules

TemperatureTemperature = = average speed of atomsaverage speed of atoms

Thermodynamics: the Study of Thermodynamics: the Study of Energy TransformationsEnergy Transformations

1st Law of Thermodynamics1st Law of Thermodynamics

Energy cannot Energy cannot be created nor be created nor destroyeddestroyed

May May changechange from from one form to one form to another another

This is known as This is known as the the law of law of conservation of conservation of energyenergy

2nd Law of Thermodynamics2nd Law of Thermodynamics Energy transfer is not 100% Energy transfer is not 100%

efficient and each energy transfer efficient and each energy transfer increases the entropy of the increases the entropy of the universeuniverse

No reaction is 100% efficientEnergy Available To Do Work Decreases Over TimeAll reactions lose energy in the form of heatHeat is a less ordered form of energy than other forms like chemical or mechanical energyThis increases entropy

Transfer of Transfer of EnergyEnergy

Transfer of EnergyTransfer of Energy Running, photosynthesis, eatingRunning, photosynthesis, eating

Chemical to mechanicalLight to chemical

Entropy is...Entropy is... The The amount of disorderamount of disorder in a in a

systemsystem Entropy always Entropy always increases over increases over

timetime (in absence of an input of (in absence of an input of outside energy)outside energy) Cleaning Cleaning

up your room ...up your room ...

Energy is Energy is lostlost in in eacheach transformationtransformation

EntropyEntropy

Quick Quick ThinksQuick Quick Thinks What is the difference between What is the difference between

heat and temperature?heat and temperature?

What are the first and second laws What are the first and second laws of thermodynamics?of thermodynamics?

Why is no reaction 100% efficient? Why is no reaction 100% efficient? (where does the energy go?)(where does the energy go?)

Quick ThinkQuick Think

What is the What is the relationship between relationship between energy and work?energy and work?

Challenging Quick ThinkChallenging Quick Think

How does the 2How does the 2ndnd law of law of thermodynamics thermodynamics help explain the help explain the diffusion of a diffusion of a substance across substance across the cell the cell membrane?membrane?

Challenging Quick ThinksChallenging Quick ThinksDescribe the forms of Describe the forms of energy found in an apple energy found in an apple as it grows on a tree, as it grows on a tree, then falls and is digested then falls and is digested by someone who eats it.by someone who eats it.

My understanding of energy is…0 - even with prompting, I can’t show my knowledge

1 - with prompting, I can show knowledge2 - I get the basics3 - I understand beyond the basics without help4 - I can apply my knowledge to homework or test

questions

Knowing that this content is essential to understanding future content, my next step is to…

Chemical Reactions Chemical Reactions

Chemical Reactions Chemical Reactions involves...involves...

Breaking bonds in reactants Breaking bonds in reactants Forming new ones to create Forming new ones to create

productsproducts EnergyEnergy is required in one direction is required in one direction

and given off in anotherand given off in another

Energy is required in one direction and given Energy is required in one direction and given off in anotheroff in another

Change of StateChange of State

Important VocabENERGY OUT

Exergonic – energy releasing

Cataboloic – breakdown reaction

Exothermic – heat releasing

ENERGY IN

Endergonic – energy requiring

Anaboloic – building reactions

Endothermic – heat absorbing

ReactionsReactionsGibb’s Free Gibb’s Free energy (G)energy (G) – – a a measure of the "useful" measure of the "useful" energy that can do energy that can do work in a systemwork in a system

Think of it as Think of it as “available” energy“available” energy

Josiah Willard Gibbs

Reactions Reactions Free energy – systems with high G are less stable are Free energy – systems with high G are less stable are

more likely to changemore likely to change

Systems with low G are more stable and less likely to Systems with low G are more stable and less likely to changechange

ReactionsReactions

During During chemical chemical reactions reactions there will be a there will be a change in the change in the free energyfree energy

ΔΔGG

ReactionsReactions ΔΔG = G G = G final statefinal state – G – G initial stateinitial state

--ΔΔG = G = spontaneousspontaneous

++ΔΔG = not G = not spontaneousspontaneous

100 C

10 C

ΔΔG = G G = G final statefinal state – G – G initial stateinitial state

The more negative The more negative ΔΔG is, the more G is, the more work that reaction can perform for the work that reaction can perform for the cellcell

CC66HH1212OO66 + 6O + 6O22 6CO 6CO22 + 6H + 6H22OO

ΔΔG = -686 kcal/molG = -686 kcal/mol

Exergonic Reactions Endergonic Reactions

Reactions that come to equilibrium can no Reactions that come to equilibrium can no longer perform worklonger perform work

They have maximum stability and low GThey have maximum stability and low G

MetabolisMetabolismm

AllAll the the chemical chemical reactions reactions that that happen in happen in an an organismorganism metabolism metabolism

concept mapconcept map

The more positive The more positive ΔΔG is, the more energy G is, the more energy is required to drive that reactionis required to drive that reaction

6CO6CO22 + 6H + 6H220 C0 C66HH1212OO66 + 6O + 6O22

ΔΔG = +686 kcal/molG = +686 kcal/mol

Sources of Free Energy for Sources of Free Energy for living thingsliving things

Sun is ultimate source of energy for most Sun is ultimate source of energy for most ecosystems!ecosystems! PhotosynthesisPhotosynthesis Organic molecules like glucoseOrganic molecules like glucose

6CO6CO2 2 +12H+12H22O+Sun ---->CO+Sun ---->C66HH1212006 6 + 6H+ 6H22O + 6OO + 6O22

Quick ThinkQuick Think Cellular respiration uses glucose, Cellular respiration uses glucose,

which has a high level of free which has a high level of free energy, and releases COenergy, and releases CO22 and water, and water, which have low levels of free energy.which have low levels of free energy.

Is respiration spontaneous or not?Is respiration spontaneous or not? Is it exergonic or endergonic?Is it exergonic or endergonic? What happens to the energy What happens to the energy

released from glucose?released from glucose?

Which of the following correctly Which of the following correctly states the relationship between anabolic states the relationship between anabolic

and catabolic pathways? and catabolic pathways?

A.A. Degradation of organic molecules by anabolic pathways Degradation of organic molecules by anabolic pathways provides the energy to drive catabolic pathways.provides the energy to drive catabolic pathways.

B.B. Energy derived from catabolic pathways is used to drive the Energy derived from catabolic pathways is used to drive the breakdown of organic molecules in anabolic pathways.breakdown of organic molecules in anabolic pathways.

C.C. Anabolic pathways synthesize more complex organic Anabolic pathways synthesize more complex organic molecules using the energy derived from catabolic pathways.molecules using the energy derived from catabolic pathways.

D.D. Catabolic pathways produce usable cellular energy by Catabolic pathways produce usable cellular energy by synthesizing more complex organic molecules.synthesizing more complex organic molecules.

E.E. The flow of energy between catabolic and anabolic The flow of energy between catabolic and anabolic pathways is reversible.pathways is reversible.

The answer is ___ because________________

The answer is not ___ because________________

Which of the following reactions Which of the following reactions would be endergonic?would be endergonic?

A.A. HCl HCl H H++ + Cl + Cl--

B.B. CC66HH1212OO66 + 6 O + 6 O22 6 CO 6 CO22 + 6 H + 6 H22OOC.C. ATP ATP ADP + P ADP + Pii

D.D. glucose + fructose glucose + fructose sucrose sucroseE.E. all of the aboveall of the above

The answer is ___ because________________

The answer is not ___ because________________

Today you learned about energy

Create an acrostic for the word Create an acrostic for the word ENERGYENERGY

E - Entropy - which is the…E - Entropy - which is the…NNEERRGGYY

ATPATP

Cells need energy to do Cells need energy to do workwork

Cells do 3 main kinds of work:Cells do 3 main kinds of work: MechanicalMechanical – contraction, movement – contraction, movement Transport Transport – movement of substances – movement of substances

against the concentration gradientagainst the concentration gradient ChemicalChemical – synthesis of polymers – synthesis of polymers

from monomersfrom monomers

ATP provides the energy for cell ATP provides the energy for cell workwork

ATP powers the cell by using the ATP powers the cell by using the energy from exergonic reactions energy from exergonic reactions to drive endergonic reactionsto drive endergonic reactions

What is ATP?What is ATP? Adenosine triphosphate – a Adenosine triphosphate – a

nucleotidenucleotide Composed of adenine, ribose, and Composed of adenine, ribose, and

three phosphate groupsthree phosphate groups

ATP ATP structurstructur

ee

Lots of ENERGY because Lots of ENERGY because all 3 phosphate groups all 3 phosphate groups are negatively chargedare negatively charged and are repelled by each and are repelled by each otherother

ATP HydrolysisATP Hydrolysis

ATPATP When ATP donates When ATP donates

a phosphate group a phosphate group ((phosphorylationphosphorylation) ) to another to another molecule,molecule, that that molecule ismolecule is phosphorylatedphosphorylated and becomes and becomes primedprimed and and energizedenergized for for specific reactionsspecific reactions

The ATP ADP CycleThe ATP ADP Cycle

More ATP is More ATP is producedproduced from ADP and from ADP and PPii by using by using the energy the energy released from released from exergonic exergonic reactionsreactions

This can be done VERY This can be done VERY quickly ~10 million molecules quickly ~10 million molecules of ATP/second/cellof ATP/second/cell

Quick CheckQuick Check1.1. What is phosphorylation?What is phosphorylation?2.2. How does ATP provide the energy for How does ATP provide the energy for

endergonic reactions?endergonic reactions?3.3. Why do the bonds between phosphate Why do the bonds between phosphate

groups in ATP store so much energy?groups in ATP store so much energy?4.4. What kind of energy is in chemical What kind of energy is in chemical

bonds? bonds?

ObjectiveExplain, using at least 3 specific details, how enzymes speed up chemical reactions

Quick ThinkQuick Think Which group has more free energy Which group has more free energy

and why?and why?

Group 1 = glutamic acid + ammonia + Group 1 = glutamic acid + ammonia + ATPATP

Group 2 = glutamine + ADP + PGroup 2 = glutamine + ADP + Pii

EnzymesEnzymes

Enzymes help drive metabolic Enzymes help drive metabolic reactionsreactions Even if a reaction is Even if a reaction is

spontaneous, it may spontaneous, it may happen too slowly happen too slowly to support the cellto support the cell

Enzymes speed up Enzymes speed up the process of the process of chemical reactionschemical reactions

Living SystemsLiving Systems ALL cellular ALL cellular

metabolism metabolism (reactions) (reactions) involve involve enzymesenzymes

Enzyme Pathways (aka metabolic Enzyme Pathways (aka metabolic pathwayspathways))

Activation energyActivation energy

Activation energyActivation energy (aka free energy of (aka free energy of activation) – the energy required to start activation) – the energy required to start a reactiona reaction

The reactants have to be energized to The reactants have to be energized to an unstable state so that they can break an unstable state so that they can break their bonds and be primed for new their bonds and be primed for new bonds to formbonds to form

So activation energy is…So activation energy is… The energy needed by molecules The energy needed by molecules

in order to reactin order to react

Reaction RateReaction Rate Initial accelerationInitial acceleration as enzymes & as enzymes &

substrates collidesubstrates collide Transition stateTransition state

Collisions at Collisions at maximum ratemaximum rate

Deceleration Deceleration as substrates as substrates used upused up

Inorganic CatalystsInorganic Catalysts HeatHeat

Activation energy is often supplied in Activation energy is often supplied in the form of heat that the reactants the form of heat that the reactants absorb from the surroundingsabsorb from the surroundings

LightLight PhotosynthesisPhotosynthesis

ElectricityElectricity Decomposition of waterDecomposition of water

Heat can damage proteins so cells Heat can damage proteins so cells use enzymes insteaduse enzymes instead

Increasing Reaction RateIncreasing Reaction Rate Enzymes Enzymes

lower the lower the activation activation energyenergy by by allowing the allowing the reactants to reactants to absorb enough absorb enough energy to reach energy to reach the transition the transition state at normal state at normal temperaturestemperatures

http://www.sumanasinc.com/webcontent/animations/content/enzymes/enzymes.html

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OptimumOptimumConditionsConditions

Each Each enzyme has enzyme has a specific a specific range of range of condition in condition in which it which it works bestworks best

Quick ThinkQuick ThinkMany spontaneous Many spontaneous reactions occur very reactions occur very slowly. Why donslowly. Why don’’t all t all spontaneous reactions spontaneous reactions occur instantly?occur instantly?

Organic CatalystsOrganic Catalysts ENZYMESENZYMES Have a Specific shapeHave a Specific shape

Active siteActive site: : crevice where substrate crevice where substrate binds to enzyme during a reactionbinds to enzyme during a reaction

EnzymesEnzymes Usually made up of 2 or more Usually made up of 2 or more

subunitssubunits

What level of What level of protein structure protein structure is this? is this?

This?This?

SubstrateSubstrate The reactant an enzyme works on is The reactant an enzyme works on is

called itcalled it’’s substrate – specific to each s substrate – specific to each enzymeenzyme

The enzyme-substrate complex

Lock & Lock & Key Key

ActionActionEnzymes Enzymes are very are very specific and specific and can even can even distinguish distinguish between between isomersisomers

Induced FitInduced Fit Binding of a substrate causes a Binding of a substrate causes a

change in shapechange in shape, INDUCING an even , INDUCING an even closer fit with substrate closer fit with substrate

This is called the inducedThis is called the induced fitfitLike a handshake

Increasing enzyme actionIncreasing enzyme action CooperativityCooperativity – – the binding of the binding of

one substrate molecule primes all one substrate molecule primes all the other subunits of that enzyme the other subunits of that enzyme for binding to additional substrate for binding to additional substrate moleculesmolecules

Enzyme activityEnzyme activity Substrate bonded to enzyme with Substrate bonded to enzyme with

weak bonds (hydrogen bonds or ionic weak bonds (hydrogen bonds or ionic bonds)bonds)

Enzyme catalyzes the reactionEnzyme catalyzes the reaction Products are released and enzyme is Products are released and enzyme is

free to do it againfree to do it again Enzymes work very fast ~ 1000 Enzymes work very fast ~ 1000

reactions/secondreactions/second

Enzyme activityEnzyme activity Most reactions are reversibleMost reactions are reversible Enzymes can catalyze the reaction Enzymes can catalyze the reaction

in either directionin either direction Always work in the direction Always work in the direction

toward equilibriumtoward equilibrium

Enzyme Enzyme activityactivity

Enzymes help by:Enzymes help by: Orienting the Orienting the

reactants properly reactants properly so they can reactso they can react

Stretching and Stretching and bending reactants bending reactants to help them get to help them get to the transition to the transition state fasterstate faster

Provides a Provides a microenvironment microenvironment more suitable for more suitable for the reaction to the reaction to occuroccurhttp://ed.ted.com/lessons/acti

vation-energy-kickstarting-chemical-reactions-vance-kite

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Animation timeAnimation time

Quick ThinkQuick ThinkDescribe why enzymes Describe why enzymes only react on specific only react on specific substratessubstrates

Enzyme activity Enzyme activity may be may be inhibited inhibited by a variety of by a variety of

factorsfactors

Inorganic InhibitorsInorganic Inhibitors1.1. HEATHEAT

Breaks bonds, causes enzymes Breaks bonds, causes enzymes to lose their tertiary shapeto lose their tertiary shape

Some enzymes will "snap back" Some enzymes will "snap back" on coolingon cooling

Some never regain their Some never regain their structurestructure

Inorganic InhibitorsInorganic Inhibitors2.2. pHpH

Change in Change in pHpH alters the alters the tertiary tertiary structure of structure of the enzymethe enzyme

3.3. Competitive Competitive InhibitorsInhibitors

Blocks the active site Blocks the active site Substrate cannot bond Substrate cannot bond

to enzymeto enzyme

Inhibiting Enzyme Inhibiting Enzyme ActionAction

4.4. Allosteric INHIBITOR Allosteric INHIBITOR MoleculesMolecules aka non-competitive inhibitorsaka non-competitive inhibitors attaches to a site that attaches to a site that

is not the active siteis not the active site Changes the shape of Changes the shape of

the enzymethe enzyme

5.5. IRREVERSIBLE INHIBITIONIRREVERSIBLE INHIBITION permanently permanently DENATURING itDENATURING it Usually due to covalent bonding with the Usually due to covalent bonding with the

enzymeenzyme Many Many toxins and poisons do thistoxins and poisons do this

Nerve gases, penicillinNerve gases, penicillin

Inhibiting Enzyme ActionInhibiting Enzyme Action

6.6. Feedback InhibitionFeedback InhibitionPathway has a product which blocks the action of Pathway has a product which blocks the action of

enzymes early in the pathway enzymes early in the pathway (turns itself off!)(turns itself off!)

Inhibiting Enzyme ActionInhibiting Enzyme Action Not always a bad thingNot always a bad thing It is one way the cell controls It is one way the cell controls

chemical reactionschemical reactions

Quick ThinkQuick ThinkWhat are some ways that What are some ways that

enzyme activity can be enzyme activity can be inhibited? inhibited?

Why is this good for living Why is this good for living systems?systems?

Enzyme activity Enzyme activity must be must be regulatedregulated

by the cellby the cell

Enzyme activityEnzyme activity1.1. Some enzymes require Some enzymes require

cofactors cofactors NonproteinNonprotein Organic or inorganicOrganic or inorganic

If organic called a If organic called a coenzymecoenzyme

Permanently attached or Permanently attached or loosely attachedloosely attached

Help enzyme functionHelp enzyme function

2.2. Allosteric ACTIVATOR moleculesAllosteric ACTIVATOR molecules Allosteric molecules Allosteric molecules must be must be

present for some enzymes to work present for some enzymes to work properlyproperly

Often ions or Often ions or vitaminsvitamins

Regulating Enzyme ActionRegulating Enzyme Action

Allosteric Allosteric molecule molecule binds to binds to enzyme and enzyme and changes it to a changes it to a functional functional shapeshape

Enzyme Enzyme PathwaysPathways

Enzyme PathwaysEnzyme Pathways AdvantagesAdvantages

Similar enzymes Similar enzymes can be can be segregatedsegregated within a cellwithin a cell

Little accumulation Little accumulation of intermediate of intermediate productsproducts

Removes product of Removes product of each reaction from each reaction from the system so that the system so that CHEMICAL CHEMICAL EQUILIBRIUM EQUILIBRIUM isis never reachednever reached mitochondrion