Pre Lab Quiz: Enzymes

What Are Enzymes and How do They Work? 

All living organisms depend on enzymes to catalyze (speed up) chemical reactions. Without enzymes, reactions would not occur fast enough to support life. There are many types of enzymes, active in all types of cells. Each reaction uses a specific enzyme.

Image Description: The enzyme produces a reaction in the substrate, resulting in a product (or products).

In enzyme driven chemical reactions, the reactant is called a substrate. The enzyme and substrate must first collide with each other due to the random molecular motion of the solution. Then amino acids lining the active site create attractions between the enzyme and its substrate. The enzyme then catalyzes the chemical reaction, produces the product. The enzyme is written above the arrow to indicate that it is unaltered by the reaction and can be used again (and again). Here is a specific example, and the one we will be using in lab. The enzyme is called catalase.

Image Description: The enzyme, catalase, generates a reaction in the substrate, Hydrogen Peroxide, resulting in the product, Water and Oxygen.

All enzymes are proteins. The amino acid sequence determines the three-dimensional shape of the enzyme. This shape is critical because it allows the enzyme to interact with its substrate molecule, the molecule that the enzyme works on. Enzyme action changes the substrate into a product(s). The enzyme itself remains unchanged in the reaction, it can be reused. Each enzyme works best at a specific temperature and pH. Most enzymes in the human body exhibit maximal activity at 37^oC and a pH of around 7. Extremes in temperature and pH can change the shape of the enzyme, rendering it inactive.

Watch this video to help visualize the information from the paragraph above. 

Are You Ready?

Take this pre-lab quiz to make sure that you are prepared for  lab.