Names: _______________________________________________________ Date: ____________________________ Period: _________
Enzyme-Controlled Reactions Virtual Lab
1. What question are you answering? ___________________________________________________________________________
Enzyme Animation: Click on the TV and use the animation to answer the following questions.
2. Are enzymes specific to a substrate or substrates? _________________________________________________________
3. Where do substrates fit on an enzyme? ______________________________________________________________________
4. Can the same enzyme be used more than once? ____________________________________________________________
More Information: Click the Information button and read about enzymes. Fill-in the blanks as you
go.
Enzymes are _________________________ that ________________ up the rate of chemical reactions. Enzymes are
______________________ catalysts. A catalyst is a ___________________________ that controls the ________________ of
a reaction, but is itself ______________ used up in the process. Reactions that are accelerated due to the
presence of _________________________ are known as ________________________-__________________________ reactions.
Enzymes are _________________________ that accelerate chemical reactions but do not ____________________
themselves in the reactions. Enzymes enable molecules to undergo chemical changes, forming new
substances called __________________________. _______________________________ are molecules that are acted
upon by enzymes. Each substrate fits into an area of the enzyme called the ____________________ site. This
fitting together is often compared to a _____________-___________-____________ mechanism.
Procedure: Follow the procedure given in the virtual lab. Record your data (# of product molecules
formed per minute x106) in Table 1 below and then enter your data into the virtual table. Click the
Graph button to help you compose a graph of your data.
Table 1. Affects of Concentration and pH on Enzyme-Controlled Reactions
Amount of
pH 3
pH 5
pH 7
pH 9
Substrate
0.5 g
1.0 g
2g
4g
8g
pH 11
Graph: Make sure to TITLE your graph, LABEL the x- and y-axis, use different colors for different
pHs, and make a LEGEND to tell us which color goes with which pH.
Journal Questions: Answer in complete sentences.
1. What happens to the initial reaction rate as substrate concentration increases? Is this a linear
relationship? ____________________________________________________________________________________________________
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2. What is the maximum initial reaction rate for this enzyme at pH 7? At what concentration of
substrate did it occur? _________________________________________________________________________________________
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3. What does your data indicate about the optimum pH level for this enzyme-catalyzed reaction? _______
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Thinking Questions:
4. Explain why the maximum initial reaction rate cannot be reached at low substrate concentrations.
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5. Enzymes function most efficiently at the temperature of a typical cell, which is 37 degrees Celsius.
Increases or decreases in temperature can significantly lower the reaction rate. What does this
suggest about the importance of temperature-regulating mechanisms in organisms? Explain.
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