Activation energy

Definition

Activation energy is the minimum amount of energy required to initiate a chemical reaction. It determines the rate at which the reaction proceeds.

5 Must Know Facts For Your Next Test

1. Activation energy acts as an energy barrier that reactants must overcome for a reaction to occur.
2. Enzymes lower the activation energy required for biochemical reactions, making them proceed faster.
3. The activation energy can be supplied in various forms, such as heat or light.
4. In biological systems, many reactions would not occur at a perceptible rate without enzymes reducing their activation energies.
5. The transition state is the high-energy state that reactants must reach before forming products.

Review Questions

• What role does activation energy play in chemical reactions?
• How do enzymes influence activation energy in biochemical reactions?
• Why is activation energy important for understanding reaction rates in biological systems?

Related terms

enzyme:

Proteins that act as biological catalysts by lowering the activation energy of reactions.

catalyst: A substance that increases the rate of a chemical reaction without itself undergoing permanent change.

transition state: A high-energy state during a chemical reaction through which reactants must pass before forming products.