Notes 36 - Enzymes (and Useful Enzyme Video)

All reactions require energy in order to occur. (This to break the bonds of the reactants and form the bonds of the products.) This is called activation energy.


Enzymes are proteins that speed up (catalyze) chemical reactions. They do this by lowering the activation energy needed to start a reaction. (They make the collisions/interactions needed in the reaction more likely to happen.)

The reactants that the enzyme works on are called substrates. The substrate(s) interact with the enzyme at a place called the active site.


The active site of the enzyme can change shape which can affect its ability to bind with the substrate and speed up the reaction. Factors that can affect enzymes include temp., pH, and salt.

Video on Enzymes