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/ani mations/content/enzymes/enzymes.html