2.5 Enzymes
Enzymes are proteins that act as biological catalysts. They speed up chemical reactions in living organisms by lowering the activation energy it takes to get a reaction to start. Usually, the processes or reactions are part of a cycle or pathway, with separate reactions at each step. Each step of a pathway or cycle usually requires a specific enzyme. Without the specific enzyme to catalyze a reaction, the cycle or pathway cannot be completed.
Basic terms that you need to know:
Active site - the place on the enzyme where the reaction takes place
Substrate - the molecule or molecules that an enzyme reacts
Products - what is made at the end of the reaction
Basic terms that you need to know:
Active site - the place on the enzyme where the reaction takes place
Substrate - the molecule or molecules that an enzyme reacts
Products - what is made at the end of the reaction
Environmental Factors That Affect Enzyme Activity
The environment of the enzyme and the substrate can affect the speed of the reaction. In some cases the environment can cause the enzyme to stop working or even unravel. When an enzyme stops working we call it "denatured." Here are some things that can affect enzyme activity:
The environment of the enzyme and the substrate can affect the speed of the reaction. In some cases the environment can cause the enzyme to stop working or even unravel. When an enzyme stops working we call it "denatured." Here are some things that can affect enzyme activity:
- Temperature - The temperature can affect the reaction rate. The higher the temperature, the faster the reaction will occur. However, at some point the temperature will become so high that the enzyme will denature and stop working.
- pH - In many cases the pH level, or acidity, of the environment around the enzyme and substrate can affect the reaction rate. An extreme pH (high or low) will typically slow the reaction or even stop the reaction altogether.
- Concentration - A higher concentration of substrate or enzyme can increase the reaction rate.
- Inhibitors - Inhibitors are molecules that are specially made to stop the activity of enzymes. They may just slow down the reaction or stop it altogether. Some inhibitors bond with the enzyme causing it to change shape and not work correctly. The opposite of an inhibitor is an activator which can help to speed up the reaction.
8.1 Metabolism (HL)
Helpful Videos, animations and websites
Northland College's What is an Enzyme? covers inhibition