[Unit 1.7] | Enzyme Action

Question 1

Define an enzyme.

Answer 1

A biological catalyst that provides an alternative reaction pathway which reduces the activation energy for reactants.

Question 2

Explain the induced fit model.

Answer 2

• The tertiary shape of an enzyme is complementary to the shape of a substrate (but it is not a perfect fit).
• As the substrate binds to the active site, the shape of the active site changes to fit neatly around it, forming an enzyme-substrate complex.
• The active site applies mechanical pressure to the substrate which stresses the bonds and lowers the activation energy at body temperature.