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
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.