View
217
Download
0
Category
Preview:
Citation preview
Objectives
• Differentiate between reactants and products in a chemical reaction.
• Describe the process of the chemical reaction and explain how enzymes catalyze chemical reactions by lowering the activation energy.
• Recognize that enzymes are specific and are not used up in a chemical reaction.
• Create analogies that demonstrate understanding of the role of enzymes.
Chemical Reaction
Reactants
ProductsActivation Energy
ENZYME
Catalyst
Substrate Active Site
Induced Fit
ENZYME
• Biological Catalyst• Catalyst = speeds up the
rate of chemical reaction by LOWERING activation energy.
• Substrate or Reactants bind to active site.
• Makes reactions happen FASTER
Active SiteActive Site
A restricted regionrestricted region of an enzymeenzyme molecule which bindsbinds to the substratesubstrate.
Chemical Reactions• Recipe Ingredients are to
Cake as Reactants are to Product
• Reactants or Substrate are the starting substances.
• Chemical reactions allow living things to grow, develop, reproduce and adapt.
• New Products are made as atoms are rearranged.
Chemical Reactions
• Reactants Products
• C6H12O6 + O2 CO2 + H20
• Just like cake is made with flour, sugar, and other ingredients mixed together, it is not cake until you bake it.
• The key to starting a chemical reaction is energy.
yieldsyields
yieldsyields
77
So How Do So How Do EnzymesEnzymes Work? Work?
Enzymes work by weakening weakening bondsbonds which which lowers lowers activation activation energyenergy
Activation Energy = minimum amount of energy needed for reactants (substrate) to form Products (new substance)
EnzymesEnzymes
FreeEnergy
Progress of the reaction
Reactants
Products
Activation EnergyActivation Energy
Without EnzymeWith Enzyme
Lowers ActivationEnergy
9
EnzymeEnzyme--SubstrateSubstrate Complex Complex
The substancesubstance (reactant) an enzymeenzyme acts on is the substratesubstrate
EnzymeSubstrateBinds to Active Site
10
Induced FitInduced Fit• A change in the shapeshape of an enzyme’s active site• Induced Induced by the substrate
Examples of Enzymes at Work
• Notice simple to more complex drawings.• Each illustrates how an enzyme works.• See if you can identify Enzyme, Reactants
(Substrate), Products, active site, and induced fit.
• Remember the job of the enzyme is to LOWER the activation energy so the chemical reaction works FASTER.
Reactants (Substrate)
Enzyme ChemicalReaction
Products
Enzyme
Notice Reactants (Substrate bind to enzyme where chemical reaction occurs faster because the activation energy is lowered (less energy needed than without enzyme). The enzyme is ready to act again and does NOT become part of the Products.
Active Site
Reactants/Substrate Products
Notice Name of Enzyme
NoticeName ofSubstrate
Name of Enzyme ends with “ASE” and is named according to its job.
Enzymes
• Have a specific job • Do NOT get used up or become part of
product.• Lowers the activation energy needed to get
the reaction started.• Makes the reaction happen faster.
Can you finish these analogies about Enzymes and create your own?
• An enzyme is to a reaction, as a ____ is to a lock.
• Ose is to a carbohydrate as ____ is to an enzyme.
• Ingredients are to a cake, as _________ are to the Product.
key
Ase
Reactants
Review Key Vocabulary and
Relate to ENZYMES
Chemical Reaction
Reactants
ProductsActivation Energy
ENZYME
Catalyst
Substrate Active Site
Induced Fit
Proceed to Quiz or Review PowerPoint
Recommended