Enzymes
Explain how enzymes function as catalysts.
What are enzymes?
• Biological catalysts - substances which
speed up reactions but which do not get used
up themselves. Enzyme names usually end in
the letters -ase, as in amylase, protease and
lipase.
Example: Enzymes are proteins.
Why are enzymes important?
• Enzymes control the chemical
reactions that happen in our
bodies.
Example: Enzymes help maintain
homeostasis
How do enzymes function?
Before
After
How do enzymes function?
• Enzymes start chemical reactions by locking
onto one of the reactants or substrate and
speeding up the reaction.
Example: Just like a key only fits into a specific
lock, each enzyme has its own specific
substrate
How does an enzyme start a
chemical reaction?
• The chemical which the enzyme locks onto is
called the substrate, and the enzyme has a
kind of chemical sensor, called an active
site, which helps it to recognize the substrate
Example:
How does an enzyme speed up a
chemical reaction?
• An enzyme lowers the activation energy.
Activation energy is the energy needed to
start a reaction.
Example: like the activation fee on a cell
phone
Animation of Enzyme Function
What are some factors that might
affect enzyme function?
Temperature and pH changes can cause a change in
the active site shape. This will not allow the enzyme
to attach to the substrate and no reaction occurs.
Examples:
Temperature and Enzyme Function
pH and Enzyme Function