Enzymes

Mrs. Harlin

4.1.3

• Explain how enzymes act as catalysts for biological reactions.

Chemical Reactions

Enzymes are proteins known as catalysts because they speed up the rate of a chemical reaction by decreasing the activation energy.– Can bind only certain substrates.– Over 4000 enzymes in a single cell in your body.– Can be used over and over again.

• Extreme temperature and pH changes can denature, meaning change the shape of the enzyme, so that it cannot bind to a substrate, meaning it no longer works.

How Enzymes Work

• Enzymes bind to a substrate at the active site. They fit like a lock and key! It is all about the SHAPE of the enzyme.

Activation Energy and Enzymes

• http://www.sumanasinc.com/webcontent/animations/content/enzymes/enzymes.html