Biology by Scientific Minds © 2011 All Rights Reserved 1
Name: _______________________________________________________________ Date: ________________________________________________
Key Points & Questions
1. Enzymes are ______________________ ______________________ that
increase the rate of a chemical reaction. Almost all processes in
living cells need enzymes to occur at an appropriate rate.
2. Enzymes are specific to what they will act upon. For instance, the
enzyme lipase acts on ______________________, and the enzyme
sucrase acts on sucrose.
3. The substance an enzyme acts on is called the
______________________, and the region an enzyme binds to is
called the active site. Enzymes act on a substrate to create a
4. Both the ______________________ and substrate possess
complementary shapes that fit together like a puzzle. Because
of this, the enzyme-substrate relationship is often referred to as
a “________________________________” model.
5. Enzyme names generally end in “-ase”, such as
______________________ and amylase. Enzymes are reusable
protein molecules that are not permanently changed by the
6. Enzymes work by lowering the ______________________
______________________ needed for a reaction to occur. Activation
energy is the minimum amount of energy required to start a
chemical reaction. Notice that the energy of activation is lower
with enzymes than without, which means the reaction will occur
more rapidly.
7. Enzyme activity can be affected by other molecules called
______________________. Inhibitors decrease or block enzyme
activity. Some inhibitors block the ______________________
______________________ while other inhibitors change the shape of
the active site. Many drugs and poisons are inhibitors.
8. Enzyme activity can also be affected by molecules called
______________________. Activators increase enzyme activity.
Biology by Scientific Minds © 2011 All Rights Reserved 2
9. Enzyme activity can be affected by ___________________________
______________________ such as temperature and pH. High
temperatures can cause an enzyme to change shape or
denature. Once denatured, the substrate no longer fits the
active site and the reaction will not occur.
10. Enzymes are essential to maintaining ______________________ in
living organisms. They are involved in cell regulation, muscle
contraction, active transport, digestion, and metabolic pathways.
11. Enzymes also have many ______________________ applications,
which include food processing, cheese making, meat
tenderizing, paper manufacturing, and genetic engineering.
Reflect and Respond
1. Homeostasis, which is internal balance in the body, is important to life. Explain how maintaining
homeostasis is especially important for enzymes.
2. Why is the shape of an enzyme vitally important to its function?
Biology by Scientific Minds © 2011 All Rights Reserved 3
3. Describe how you would design an experiment to investigate the action of amylase on starch.
4. What is the role of enzymes?
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