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Enzymes - Level
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1. Enzymes - LevelI. Enzymes are proteins and have a 3D shape.
II. Enzymes turn the food we eat into energy and unlock this energy for use in the body.
III. Act as catalyst to accelerate a reaction. IV. Not permanently changed
in the process.
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1. EnzymesV. Enzymes are specific for what they
will catalyzeVI. Are reusableVI. End in – ase
a. Examples: -Sucrase -Lactase -Maltase
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1. Enzymes
VII. How do enzymes work?
a. Enzymes work by weakening bonds which lowers activation energy
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1. EnzymesVIII. How do enzymes function?
a. Enzymes attach to molecules called substrates, forming the enzyme-substrate complex:
i. The substrate is the molecule that the enzyme acts upon.
EnzymeSubstrate Joins
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1. Enzymeb. The substrate enters a specific location on the
enzyme known as the active site.
i. Active site: A restricted region of an enzyme molecule which binds to the substrate.
EnzymeSubstrate
Active Site
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1. Enzymesc. Induced Fit: A change in the shape of an
enzyme’s active site
i. Induced (started) by the substrate
ii. A change in the configuration of an enzyme’s active site.
Enzyme
Active Sitesubstrate
induced fit
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1. Enzymes
Enzyme may be used againEnzyme-
substrate complex
E
S
P
E
E
P
Reaction coordinate
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1. Enzymes
IX. What Affects Enzyme Activity?
a. Two factors:
1. Environmental Conditions
2. Enzyme Inhibitors
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1. Enzymes
1. Environmental Conditions: A . Extreme Temperatures are the most
dangerous.
i. High temps may denature (unfold) the enzyme.
B. pH (most like 6 - 8 pH near neutral)
C. Ionic concentration (salt ions)
1. EnzymesV. The pH scale is a measure of
the concentration of hydrogen ions (H+) in a solution. The scale runs from 0 – 14. Pure water has a pH of 7.
1. Basic solutions have pH values above 7.
2. Acidic solutions have a pH below 7.
• 3. Each number on the scale has 10 times the number of hydrogen ions as the number before it.
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1. Enzymes
2. Two examples of Enzyme Inhibitors:
a. Competitive inhibitors: are chemicals that resemble an enzyme’s normal substrate and compete with it for the active site.
Enzyme
Competitive inhibitor
Substrate
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1. Enzymes
3. Two examples of Enzyme Inhibitors:b. Noncompetitive inhibitors: Inhibitors that do not enter the active site, but bind to another part of the enzyme causing the enzyme to change its shape, which in turn
alters the active site.
Enzymeactive site altered
NoncompetitiveInhibitor
Substrate
14http://www.youtube.com/watch?v=PILzvT3spCQ
1. Enzymes