Potential Energy (E P ) : Energy that is stored , either as energy of

Potential Energy (EP) : Energy that is stored , either as energy of position, or chemical energy

Enzymes and Energy TransferThere are three types of energy in the universe.

Ex; Energy stored in a stretched rubber Band (position energy ) or in the food that you eat (chemical energy)

3) Kinetic Energy (EK) Energy of movement and heat

2) Activation Energy (EA): Energyrequired to begin a reaction

Ex: Pushing a wagon to start it down a hill,the energy needed to start a chemical reaction.

Ex: A ball rolling down a hill(Movement)

A match burning (Heat)

(Striking a match)

EK=EP-EA

Kinetic Energy equals Potential Energy minus Activation Energy

-in other words, all the potential energy (100%)would be converted.

-Lowering EA to zero would makeEK = EP (100% efficiency)

EnzymesEnzymes are complex molecules made of protein

Enzymes work by lowering the activation energy (EA) of reactions

Pot

enti

al E

ner

gy

Kin

etic

En

ergy

Enzymes are very specific for the molecules that they will work on.

The molecules that enzymes work on are called the substrate.

-Similar to a Lock and Key, only the correct key will fit the lock.

SUBSTRATE

1)Substrate (maltose) and enzyme come

together

3) The enzyme puts a strain on the bond, breaking it. 2 smaller glucose molecules result.

2) Substrate fits exactly in the enzyme, and bond is over the active site of the enzyme

Substrate 1 Substrate 2

Active Sites on Enzyme

Enzyme

1) Substrate molecules are attracted to the activesites on the enzyme

Substrate 1 Substrate 2

Enzyme

2) Substrate molecules arefirmly held by the enzymeat the active sites. Molecules are oriented sothat bonding areas face together.

Substrate 1 Substrate 2

Enzyme3) Substrate molecules cannow bond easily, becausethey are held in the properorientation.

Substrate 1 Substrate 2

Enzyme

New Substrate 1 New Substrate 2

4) Original substrate moleculesare released, making room for two new molecules, and the process is repeated over and over.

Coenzymes:-Molecules that help with theenzymatic reaction. (Make the reaction even more efficient)

-Coenzymes are often vitamins or minerals

Types of Chemical Reactions1)Exergonic (exothermic): Once

started, gives off energy (heat) Ex: Fire, “heat pack”

Heat pack: Mg + H20 = Mg(OH)2

+ H2 + heat

2) Endergonic (endothermic): Reaction uses energy, needs a constant input of energy (heat)

Ex: Cold Pack

-barium hydroxide and

ammonium nitrate

The source of energy for most cellular endergonic reactions is ATP.ATP: Adenosine Triphosphate

A P P P

High Energy Bonds

Where does all that energy GO?

A P P P

A P P P

ATP Becomes ADP, plus a free phosphate, plus free energy

High in potential energy

Lower in potential energyEnergy is given off

The free energy is used to Power other reactions within the cell.

Examples:Protein synthesisDNA synthesis

The source of energy to make ATPis cellular respiration.

Cellular Respiration: “Burning” of sugar (glucose) to fuel cell reactions.

Aerobic vs. Anaerobic Respiration

Aerobic: Takes place in the presenceof oxygen

C6H12O6 + 6O2

6CO2+6H2O

Plus energy for 38 ATPs

Anaerobic: Takes place in the absence of oxygen

C6H12O6

2CH3CHOHCOOH(Lactic Acid)

Plus energy to create 4 ATPs

Fermentation: A form of anaerobic respiration that produces CO2 and alcohol from sugar

C6H12O6

2C2H5OH + 2CO2

Plus energy for 4 ATPs(Alcohol)