Eastern Regional High School
Honors Biology
Name: ANSWER KEY
Period: ____ Date: ______________________
Unit 4 - Enzymes and Reactions
Worksheet - Enzymes
Part I
Directions: Identify the labeled items in the diagram below:
A.
C.
B.
D.
X.
Stage I
A.
B.
C.
D.
X.
Stage I.
Stage II.
Stage III.
Stage II
Stage III
Active Site
Substrate
Enzyme-Substrate Complex
Product
Enzyme
Free Enzyme and Free Substrate
Enzyme Substrate Complex
Free Enzyme and Free Product
Part II
Directions: Answer the following questions based on your knowledge of enzymes.
1. What is an enzyme?
Biological catalysts
2. How can enzymes affect a reaction?
Enzymes speed up reactions by lowering the activation energy barrier needed for
reactions to take place
3. What is the induced fit mechanism of enzyme binding?
The substrate causes the enzyme to change it’s shape, slightly, thus allowing for a
better fit of the substrate in the active site of the enzyme. Enzymes are flexible.
4. Explain the difference between catabolism and anabolism.
Metabolism is the net results of catabolic and anabolic reactions.
Catabolic reactions are bond breaking, exergonic reactions
Anabolic reactions are bond forming, endergonic reactions
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5. Using the graph below, explain the functions of an enzyme.
Enzyme sloering activation enrgy and allow
reactions to occur more rapidly. The graph
shows the Ea with an enzyme and without an
enzyme.
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6. Which two environmental factors or conditions can affect enzyme activity? Explain how they affect the
activity level.
pH and temperature can affect enzyme shape and function. Enzymes that are moved
into exptreme pH or temperature ranges can become denatured and cease to
function.
7. Using the diagram below, explain how each enzyme is affected by changes in pH and temperature.
All enzyme shave an optimal pH and temperature.
Enzyme activity decreases as you move away from
optimal conditions.
Heat resistant bacteria have enzymes that can
function in higher temperatures. Human enzymes
Would be denatured at such high temps
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Likewise, Pepsin can only function at very acidic
pH levels. Trypsin would be deactivated in a low
pH environment. Pepsin would be denatured in
a basic environment.
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