How Enzymes Function Enzymes are biological catalysts. They can increase the rate of chemical reactions as much as a millionfold by lowering the energy barrier of a reaction. Part A - Enzymes and activation energy The graph presents three activation energy profiles for a chemical reaction (the hydrolysis of sucrose): an uncatalyzed reaction, and the same reaction catalyzed by two different enzymes. Rank these by reaction rate, as measured by the rate of product formation (from the most product formed to the least product formed). To rank items as equivalent, overlap them.
Part B - Factors that affect enzymes Complete this vocabulary exercise relating to enzymes. Match the words in the left-hand column to the appropriate blank in the sentences in the right-hand column. HelpReset cofactor specific denatured substrate active site catalyst complex
1. An enzyme is when it loses its native conformation and its biological activity.
2. An enzyme is considered a because it speeds up chemical reactions without being used up.
3. An enzyme is considered because of its ability to recognize the shape of a particular molecule.
4. A , such as a vitamin, binds to an enzyme and plays a role in catalysis.
5. When properly aligned, the enzyme and substrate form an enzyme-substrate (ES) .
6. A substrate binds to an enzyme at the , where the reaction occurs.
7. In a catalyzed reaction a reactant is often called a .