5.5 Enzymes are proteins that speed up specific reactions in cells

• activation energy is the minimum amount of "start up" energy possible


• catalysts are compounds that speed up chemical reaction


• the main catalysts of a chemical are specialized proteins called enzymes


• a specific reactant acted upon by enzymes is called the enzyme's substrate


• the substrate is in a region called the active site


• the fit between the substrate and an enzyme is smooth


• a way that an enzyme can lower the activation energy is by accepting two reactant energies

Concept Check

1. Explain the role of activation energy in a reaction. how does an enzyme affect activation energy.

The role of activation energy in a chemical reaction is to get things moving. In fireworks you need too light the fuse to have the firework go off.

2. Describe how a substrate interacts with an enzyme.

A substrate is surrounded by an enzyme and the ridge between them is smooth.