1. Enzymes

2. Enzymes – a special type of protein
Enzymes are biological catalysts, which work to speed up a chemical reaction.
Without enzymes, several reactions in cells would never occur or happen to slowly to be useful.

3. Enzymes lower activation energy.
Activation energy is the energy needed to get a chemical reaction started

4. Effect of Enzymes
When activation energy is lowered, the reaction speeds up.

5. Enzyme Action
Enzymes provide a site where reactants can be brought together to react.
This is site is called the active site.
The reactants are called the substrates.
The shape of an enzyme is so specific that generally only one enzyme will work for one substrate.
Therefore, enzymes are said to fit together like a “lock and key.”

6. Enzyme Action
Since only the substrate changes during the reaction, the enzyme can be reused again and again.

7. Enzymes can be turned on and off.
Enzymes work best at specific temperatures and pH.
Heating can change the enzyme shape and the wrong pH affects the binding of the substrate to the enzyme.
Ergo, enzymes in our body work best at 37°C (98.6°F) and at a pH between 6.5 to 7.5.
Also, most cells contain proteins that turn enzymes on or off during critical stages of development.