Written by Kelly A. Hogan, University of North Carolina at Chapel Hill
– To practice using terms related to enzyme-catalyzed reactions
– To address a misconception that enzymes are depleted after a reaction
Activity Description: Students are given a list of words and instructions to design their own enzyme-mediated reaction. Students work in small groups to design and then demonstrate their idea to the class (students can use simple props). The whole class can decide if the demonstration is designed well to illustrate understanding. The activity can work in a small class or a large class in which only a few groups get to demonstrate. You may also choose to simply demonstrate your own example asking students to come up with ideas as you prompt them.
Time Needed: Activity may take 40 minutes (if students do group work outside of class) and may take much longer if group time is given during class
Materials Needed: Variable depending on students
Tell students that they will design an enzyme-catalyzed reaction (could be dehydration synthesis, hydrolysis, functional group transfer, etc.) that shows their understanding of the words/ideas below. The materials students have available can be props available in a classroom, such as classmates, paper, pens, etc. You may suggest that students work outside of the class and plan ahead to bring simple props with them. Groups will demonstrate their ideas to the class. You may want to have a panel of student judges (American Idol style).
Ideas that students can demonstrate:
A. active site
D. enzymes are used over and over.
E. enzymes can be inhibited at their active site or their allosteric site.
F. enzyme activity is affected by environmental conditions.
Example: I place a bowl of wrapped candies on my table. I tell them that I am unwrappase. The substrate is wrapped candy and the product is unwrapped candy. My hands are the active site. A single me can unwrap many candies (enzymes are used over and over and are unchanged). The rate of me producing unwrapped candies would slow down if pistachio nuts were mixed into my bowl because the pistachio nuts would temporarily bind to my active site. Pistachios would be competitive inhibitors. If a scarf was tied around my elbows to connect them behind my back, the active site would be altered because my hands would open up and I would have trouble holding the candy. The scarf would be an allosteric inhibitor. Ideally, I work best at room temperature. If the heat was turned way up or way down my activity might be slowed by these environmental conditions, and I might be cranky and produce less product.