AP Biology Energy, atp, and enzymes

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

Reactions Reactions When When ΔΔGG is negative, the is negative, the

reaction will occur reaction will occur spontaneouslyspontaneously

Reactions that have a Reactions that have a ΔΔGG value value or zero or more are never or zero or more are never spontaneousspontaneous

--ΔΔG = G = spontaneousspontaneous

++ΔΔG = not G = not spontaneousspontaneous

Exergonic Reactions Endergonic Reactions

ReactionsReactions

If we know what If we know what reactions have a reactions have a negative delta G, negative delta G, we can determine we can determine which reactions which reactions will release energy will release energy that can be used that can be used to do work in the to do work in the cellcell Exocytosis – work Exocytosis – work

for the cell for the cell (requires energy)(requires energy)

Most reactions are Most reactions are reversiblereversible

Reversible reactions will Reversible reactions will approach approach dynamic dynamic equilibriumequilibrium

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

They have maximum They have maximum stability and low Gstability and low G

ReactionsReactions

MetabolisMetabolismm

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

concept mapconcept map

ReactionsReactions

If the reactions of If the reactions of metabolism reach metabolism reach equilibrium, a cell equilibrium, a cell could no longer do could no longer do workwork

The constant flow of The constant flow of materials into and out materials into and out of the cell prevent the of the cell prevent the cell from ever cell from ever reaching equilibriumreaching equilibrium

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

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

Before cells can use the energy of sunlight Before cells can use the energy of sunlight or that stored in carbohydrates, they must or that stored in carbohydrates, they must transfer the energytransfer the energy to molecules of ATP to molecules of ATP

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

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

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

phosphate groupsphosphate groups Cell's chief energy source for cellular Cell's chief energy source for cellular

work.work.

ATP structureATP structure Bonds Bonds between between

phosphate groups phosphate groups can becan be broken broken offoff by hydrolysisby hydrolysis

This is an This is an exergonic reaction exergonic reaction and releases 7.3 and releases 7.3 kcal of kcal of energy/mole of ATPenergy/mole of ATP

This is a bit more energy This is a bit more energy than most other molecules than most other molecules release because release because all 3 all 3 phosphate groups are phosphate groups are negatively chargednegatively charged and and are repelled by each otherare repelled by each other

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 phosphorylated phosphorylated and becomes and becomes primedprimed and and energizedenergized for for specific reactionsspecific reactions

Energy is released from storage Energy is released from storage molecules like ATPmolecules like ATPin in controlled controlled stepssteps via a via a series of series of intermediate intermediate moleculesmolecules

Similar to staircases where electrons Similar to staircases where electrons flow downflow down the steps from the top (most the steps from the top (most energy) to the bottom energy) to the bottom (least energy), (least energy), releasing a releasing a small amountsmall amount at at each stepeach step

Electron Transport SystemElectron Transport System

Energy is Energy is harnessed to harnessed to move hydrogen move hydrogen ionsions

HH++ ions ions establish pH establish pH and and electric gradients electric gradients necessary necessary for for ATPATP production production

Electron Transport SystemElectron Transport System

The ATP ADP CycleThe ATP ADP Cycle

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

Warm up QuestionsWarm up Questions1.1. 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

Begins with a specific molecule, which Begins with a specific molecule, which is altered through a series of steps, is altered through a series of steps, and ends with a specific productand ends with a specific product

How it works:How it works:

Product 1 + (enzyme 1)--> Product 2 + (enzyme 2)-->Product 3 + (enzyme 3)-->

Final ProductFinal Product

Enzyme Pathways (aka metabolic pathways)Enzyme Pathways (aka metabolic pathways)

Chemical reactions involve both Chemical reactions involve both bond breaking and bond formingbond breaking and bond forming

Synthesizing molecules = Synthesizing molecules = anabolic pathwaysanabolic pathways

Breaking down molecules = Breaking down molecules = catabolic pathwayscatabolic pathways

Complete the sentence: Endergonic/ExergonicEndergonic/Exergonic reactions occur along anabolic/catabolic anabolic/catabolic pathways because _____________________

Activation energyActivation energy

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

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

Activation energyActivation energy Heat speeds up reactions – BUTHeat speeds up reactions – BUT

harms cells harms cells tends to speed up all reactions, not just tends to speed up all reactions, not just

the ones the cell needsthe ones the cell needs Instead, cells use enzymes to catalyze Instead, cells use enzymes to catalyze

reactionsreactions

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

Animation timeAnimation time

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

subunitssubunitsWhat 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 reactants properly so they properly so they can reactcan 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 microenvironmenmicroenvironment more suitable t more suitable for the reaction to for the reaction to occuroccur

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

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 inhibited may be inhibited by a variety of by a variety of

factorsfactors

Inorganic InhibitorsInorganic Inhibitors 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 Inhibitors pHpH

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

Competitive InhibitorsCompetitive Inhibitors Blocks the active site Blocks the active site Substrate cannot bond Substrate cannot bond

to enzymeto enzyme

Inhibiting Enzyme Inhibiting Enzyme ActionAction

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

IRREVERSIBLE INHIBITIONIRREVERSIBLE INHIBITION Substances that permanently change the Substances that permanently change the

tertiary shape of an enzyme, tertiary shape of an enzyme, DENATURING ITDENATURING IT Usually due to covalent bonding with the Usually due to covalent bonding with the

enzymeenzyme Many toxins and poisons do thisMany toxins and poisons do this

Nerve gases, penicillinNerve gases, penicillin

Inhibiting Enzyme ActionInhibiting Enzyme Action

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 regulated must be regulated

by the cellby the cell

Enzyme activityEnzyme activity Some enzymes require Some enzymes require

cofactorscofactors 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

Allosteric regulationAllosteric regulation 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

Increasing Enzyme ActionIncreasing Enzyme Action Allosteric ACTIVATOR moleculesAllosteric ACTIVATOR molecules

Holds substrate in place or causes Holds substrate in place or causes a shape change in the enzyme so it a shape change in the enzyme so it ““fitsfits”” substrates better substrates better

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