1. ENZYMES….. The protein catalyst
Learning targets:
I can:
Define what an enzyme is and explain its role in the body
Explain and Identify the parts of the Lock and key model
Describe the environmental conditions that alter the shape of an enzyme
Name/identify an enzyme based on its substrate
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2. Enzyme video
Amoeba sisters video:
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3. Chemical Reactions Reactants Products 2 H2 + O2 2 H2O
Reactants- things that start the reaction (left side of arrow).
Products- things that are produced (right side of arrow).
2 H2 + O H2O
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4. I. What is an Enzyme? Organic catalysts made of proteins
ALL Enzymes are proteins (chains of amino acids folded into a specific shape).
Catalyst: substance that speeds up the rate of a chemical reaction by lowering the activation energy needed to start it without being altered or used up during the reaction
May be organic or inorganic (water)
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5. Most enzymes end in -ase
Enzymes are named according to the substrate they are specific to
Examples:
Maltase binds to maltose
Lactase binds to lactose
Lipase breaks down fat
Amylase is found in saliva
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6. II. Functions of Enzymes in living things
Help to release energy (cellular respiration) in the form of ATP to the cells so they can carry on metabolic activities (& life functions)
DIGESTION (breakdown) and SYNTHESIS (building up) of molecules
PHOTOSYNTHESIS (capturing energy)
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7. III. Enzyme Terms: Substrate: Molecule an enzyme acts upon
Usually the enzyme is larger than the substrate (reactant)
Active Site:
Region on the enzyme that fits exactly with the substrate and where the chemical reaction occurs
Coenzymes such as vitamins can combine with an enzyme so the substrate will fit into the active site better.
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8. IV. How Enzymes Work: The Lock & Key Model of Enzyme Action
DEMO
The enzyme has an active site on its surface which has a very specific shape which determines its function.
this is known as ENZYME SPECIFICTY.
Ex: Salivary Amylase Reacts with starch but not protein
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9. The enzyme and the substrate temporarily join together forming the ENZYME SUBSTRATE COMPLEX
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10. Each ENZYME is SPECIFIC for ONLY one SUBSTRATE (like a lock and key)
Once the E-S Complex is formed, the enzyme reaction takes place.
Upon completion of the reaction, the enzyme and product(s) SEPARATE, and the enzyme can be RECYCLED (REUSED)
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11. Substrate Product
Digestion reactions
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12. Digestion reaction Digestion reactions Starch amylase
Many Simple Sugars
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13. Substrate Product Synthesis Reaction
Active site
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14. Glucose or Simple Sugars
Synthesis reaction
Glucose or Simple Sugars
amylase
Starch
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15. V. Factors Limiting Enzyme Action
Denature – change in the SHAPE of the enzyme
the active site can’t bind with the substrate and the reaction rates decrease or may stop all together
This is due to strong acids (low pH) or bases (high pH) and high temperatures
Loss of SHAPE = Loss of FUNCTION
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16. Each type of enzyme require optimum (best) conditions
1. pH: dependent on location.
Pepsin works best in a pH of 3 in stomach
Tryspin works best in a pH of 7.8 in small intestine
stomach
Small intestine

17. 2. Temperature: Humans: best at 37°C
Why do we get a fever when we get sick?
b/c high temps denature (change) the shape of the enzyme and stops it from working
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18. 3. Concentration of Enzyme and Substrate
Enzyme rate also depends on the amount of enzyme and substrate
Little enzyme, lots of substrate:
Slower rates
How can we speed up the rate?
Add more enzyme until max. rate achieved.
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19. Let’s practice some regent’s questions:
1. All chemical breakdown processes in cells directly involve
 reactions that are controlled by catalysts
enzymes that are stored in mitochondria
the production of catalysts in vacuoles
enzymes that have the same genetic base sequence
2. Which statement best
describes the enzyme
represented in the graphs?
This enzyme works best at a temperature of 35°C and a pH of 8.
This enzyme works best at a temperature of 50°C and a pH of 12.
Temperature and pH have no effect on the action of this enzyme.
This enzyme works best at a temperature above 50°C and a pH above 12
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20. This diagram best illustrates the relationship between
3. The diagram below represents a series of reactions that can occur in an organism.
This diagram best illustrates the relationship between
enzymes and synthesis
amino acids and glucose
antigens and immunity
ribosomes and sugars
enzyme
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21. 4. The diagram illustrates a biochemical process that occurs in organisms.  The substance labeled "catalyst" is also known as
a hormone
an enzyme
an antibody
an inorganic compound
5. The effect of temperature on the relative rate of action of an enzyme is represented in the graph. The optimum temperature for the action of this enzyme is approximately
15°C
22°C
37°C
50°C
You should never guess-draw the line to help you
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22. Base your answer on the reactions shown in the graphic
Base your answer on the reactions shown in the graphic. The X in each reaction represents various
energy sources
final products
reactants
enzymes
Glucose is the reactant (substrate)
Right side of arrow is the product
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23. Enzyme song
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