What I need to know about
the Molecules of Life: ENZYMES
1. Explain the function of enzymes in the body.
Using the following words to help you fill in the blanks…
pH, slowly, glucose, speed up, specific, temperature, shape, products,
proteins, catalysts, unchanged, optimum
Enzymes are special _________________ that act as
____________ in living cells. A catalyst helps _____________
chemical reactions that occur in your body. Without catalysts, many
processes within your body would occur very __________. Enzymes
are highly ___________, which means that they work with one
Label the enzyme,
substance. Take the enzyme amylase, which is found in your saliva.
substrate, and active site.
This enzyme helps to break down starch into ______________.
This enzyme will only break down starch and no other substance. An enzymes’ activity is
determined by its _____________. When the reaction is completed, the enzyme and the
newly formed _____________ separate, leaving the enzyme ____________________. Each
enzyme has an _________________ range of ___________________ and _____ at which it
operates most efficiently.
2. Explain how enzyme work in the body.
Explain why the enzyme-substrate complex is known as the “lock-and-key model”
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What happens in a living organism when enzymes don’t function correctly?
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The value of achievement lies in the achieving. –Albert Einstein
Describe what is happening in each step below:
Step 1
Step 3
Step 2
Step 1
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Step 2
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Step 3
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The value of achievement lies in the achieving. –Albert Einstein
3. Analyze the factors that affect enzyme action.
Why does the line showing the rate of reaction
increase and then level off?
a. The enzyme molecules are all occupied.
b. The enzyme has become denatured.
c. The enzyme has changed.
What would happen to the enzyme if the pH of the experiment were changed to 10?
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According to the graph to the left, what is the
optimum temperature for this particular enzyme?
a. 30˚ C
b. 60˚ C
c. 40˚ C
What does denature mean?
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Why does a denatured enzyme slow the reaction rate?
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According the graph, at what pH is the enzyme
able to function at its best?
___________
Explain why you choose this particular pH.
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What can you do to this enzyme to decrease its activity? ____________________________
The value of achievement lies in the achieving. –Albert Einstein
Which enzyme requires a very acidic environment?
Pepsin or Trypsin
Which enzyme has more activity at pH of 8?
Pepsin or Trypsin
At what pH do both enzymes have the same rate of
reaction? ______
At what pH does Pepsin work best? _____
What would happen if pepsin was placed in the small intestine (pH of 8)?
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4. Quick Quiz
1. Most enzymes are
A lipids
B carbohydrates
C proteins
D nucleic acids
2. Enzymes are catalyst, this means that
they
A reduce the chemical reaction
B speed up the chemical reaction
C stop the chemical reaction
D have nothing to do with the
chemical reaction
3. An enzyme’s activity is determined by
A its shape
B other enzymes
C its size
D its surface area
4. Two factors that can affect the enzyme
activity is
A surface area and size
B shape and other enzymes
C temperature and size
D temperature and pH
5. After the reaction is complete, the
enzyme is
A changed
B unchanged
6. The point where the enzyme and the
substrate meet is called the
A enzyme site
B active site
C meeting site
D activation site
The value of achievement lies in the achieving. –Albert Einstein
5. Explain how to test enzyme in a laboratory experiments
Catalase is an enzyme found in the tissues of
plants and animals, including humans.
Catalase helps prevent a toxic buildup of
hydrogen peroxide in cells by breaking it
down into water and oxygen gas. Several
students conduct an experiment to test the
effects of pH on the activity of catalase.
Each test tube contains a solution of
hydrogen peroxide and water at various pH
levels. The liver tissue is a source of
catalase. The diagram represents the results
of their experiment.
What problem are the students trying to investigate?
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What is the independent variable?
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What is the dependent variable?
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Which test tube is the control group? Why?
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Create a data table to explain the student’s results.
The value of achievement lies in the achieving. –Albert Einstein