1. ENZYMES

2. ___________ HELP CHEMICAL REACTIONS _______________ HAPPEN FASTER
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CATALYSTS
___________ HELP CHEMICAL REACTIONS _______________
HAPPEN FASTER
Catalysts work by ____________ the
___________________________to get a chemical reaction started.
DECREASING
ACTIVATION ENERGY required

3. CATALYSTS in Living Things
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CATALYSTS in Living Things
In living systems __________ that
________________to control chemical reactions are called
= _________
PROTEINS
act as catalysts
ENZYMES
SEE ANIMATION of AMYLASE
More about this in Chapters 7,8,9 and 12

4. Energy in Reactions
*** Energy is released or absorbed whenever chemical bonds form or are broken ***
Chemical reactions involve changes in energy
Activation energy – energy needed to start a chemical reaction

5. Enzymes
Some reactions are much too slow and need something to speed them up – that’s why we need enzymes
Enzymes -proteins that speed up chemical reactions, or act as a catalyst
Catalyst – substance that speeds up a chemical reaction with out being consumed by the reaction – therefore lowering the activation energy Most enzyme names end in –ase
Very specific

6. How do enzymes work? enzymes
Provide a site where reactants can be brought together to react. Reactants are called substrates
Substrates bind to the enzymes “active site” like a puzzle and they remain together until the reaction is done.
Involved in almost all metabolic processes.
Ex. Speed up reactions in digestion of food, synthesis of molecules, and the storage and release of energy.
enzymes
Thinking question – have you ever heard the word enzyme? What was it referring to?

7. Enzymes are reuseable
Enzymes can be used over and over again – they are not consumed by the reaction.
Enzymes can be denatured (lose their shape) if they are exposed to high temperature or a change in pH.
Enzymes in the body work at a pH of 7

8. Common enzymes
Lactase – responsible for breaking down the lactose in dairy products – those that do not have it are “lactose intolerant”

9. ______________ to get a chemical reaction _______________
= ________________________
Energy required
STARTED
ACTIVATION ENERGY
ACTIVATION ENERGY
REACTANTS
PRODUCTS
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10. PROTEINS CAN BE ENZYMES
SUBSTRATE
ENZYME-SUBSTRATE
COMPLEX
ENZYME Unchanged
& Reusable
PRODUCTS
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11. Click HERE to learn more about enzymes
ENZYMES _____ like
a _______________
to only _________of _________.
Enzymes are ___________ by the reaction and ___________
FIT
LOCK AND KEY
SUBSTRATE
ONE KIND
UNCHANGED
REUSABLE

12. FACTORS THAT AFFECT ENZYME ACTIVITY
__________ & ______________
Conditions that are TOO ACIDIC
or TOO HOT cause proteins to
________ or _________ pH
temperature
UNWIND DENATURE
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13. changes shape ACTIVE SITE CAN’T BIND
Denaturing _______ the _______ of the ______________ so enzyme ______________ to ____________
changes
shape
ACTIVE SITE
CAN’T BIND
SUBSTRATE
_______________ (keeping pH and temperature constant) is ______________ for maintaining ____________________
HOMEOSTASIS
IMPORTANT
ENZYME FUNCTION
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14. -ASE
Many enzyme NAMES end in _____
and the beginning of the name tells what it does
DNA Polymerase= “polymerizes”
joins monomers to make DNA
Protease=
breaks down proteins
ATP synthase= synthesizes ATP