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Enzymes and Energy Transfer. There are three types of energy in the universe. Potential Energy (E P ) : Energy that is stored , either as energy of position, or chemical energy. Ex; Energy stored in a stretched rubber Band (position energy ) or in the food that - PowerPoint PPT Presentation
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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)
