An enzyme reduces activation energy and increases reaction rate of a biochemical reaction.
Activation energy is the energy required for a reaction to occur and determines its reaction rate. Catalysts are substances that increase the reaction rate by lowering the activation energy needed for the reaction to occur. Enzymes act as a catalyst by lowering the activation energy required to initiate the biochemical reaction. When the activation energy required for a reaction is reduced, the reaction rate increases and can happen more quickly.
Diagram of a catalytic reaction showing difference in activation energy in uncatalysed and catalysed reaction. The enzyme reduces the energy barrier required to activate the substrate, allowing more substrates to become activated, which increases the rate of product formation. Note that the energy difference between the substrate and the product is not changed by the enzyme.
Practice Questions
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Key Points
• Activation energy is the energy required for a reaction to occur and determines its reaction rate.
• Catalysts are substances that increase the reaction rate by lowering the activation energy needed for the reaction to occur.
• Enzymes act as a catalyst by lowering the activation energy required to initiate the biochemical reaction.
• Enzymes reduce activation energy and increase the reaction rate of a biochemical reaction.
Key Terms
Catalyst: A substance that increases the rate of a chemical reaction without being consumed in the process.
Activation energy: The minimum amount of energy that molecules must have in order for a reaction to occur upon collision.
Enzyme: A substance produced by a living organism which acts as a catalyst to bring about a specific biochemical reaction.
