For the enzymes and kinetics portion of the unit, I will extend student learning to biochemistry. Specifically, I will teach the principles of Michaelis-Menten kinetics using a classroom teaching technique adopted from William Moran. Firstly, enzyme kinetics is not a simple concept to grasp. Students are forced to tackle multiple constants (K
m
and V
max
) and graphs while keeping in mind a temporal biochemical image of the actual enzyme and substrate. Unfortunately, for many of my students, the task of processing equations and graphs is daunting, meaning they might miss out on truly understanding enzyme kinetics. This exercise will help remedy that.
The classroom exercise that I have chosen to implement is simple and allows students to view the turnover as an enzyme catalyzes a reaction. The full activity is detailed in the labs section. The activity involves students mimicking the enzyme with the students’ hands representing the enzymes active site. Popsicle sticks are used as substrate molecules and the catalytic event is the breaking of the Popsicle stick into two pieces. In this way, students will be able to see that as Popsicle stick concentration increases the number of Popsicle sticks broken per unit time will also increase. Then, at saturating Popsicle stick concentrations, or when students are unable to break Popsicle sticks at a faster rate, the rate of turnover will be limited and students will see the initial rate (V
0
) approach some maximum (V
max
). With this short and simple experiment, students get a hands-on appreciation for multiple important ideas: 1) At relatively low substrate concentrations, the rate of the reaction varies linearly with substrate concentration. 2) As the enzymes’ active sites are saturated, the rate of reaction reaches a maximum 3) Turnover rate is independent of the substrate concentration and dictates the maximum rate of reaction.
Additionally, students will generate a saturation curve (See Figure 4). Students will determine K
m
by analyzing the graph and gain an understanding of its importance as a dissociation constant.