In order to better understand how enzymes work by speeding up chemical reactions, AP Biology students worked recently with Dr. Christine Pickett, Upper School Science Teacher, to conduct lab experiments that measured the reaction between enzymes and substrates in different environments.
The juniors and seniors in the Cellular Energetics class measured the amount of oxygen gas produced through a reaction where catalase enzyme from yeast was added to hydrogen peroxide to form oxygen gas. In five different scenarios, the students watched as oxygen gas was produced from the reactions. They then measured the resulting gas. Students observed how the enzyme reactions were affected by temperature (including ice and boiled catalase), enzyme concentration, substrate concentration, pH levels, and ionic concentration (added salt).
As the temperature rose, so did oxygen production—to a point. When the temperature rose to boiling, little to no oxygen was produced. Introducing differences in pH had similar results. Students saw a decrease in oxygen production as vinegar (acid) and baking soda (base) materials were incorporated, and an increase in oxygen production with the scenario at a neutral pH level. When students concentrated the catalase they observed an increased in oxygen production, just as they did when they concentrated the substrate. But increasing the salt levels followed a similar path to the increase in temperature, with oxygen production climbing with the introduction of salt, but falling as the salt level continued to rise.
What does this data mean and how can students use the information? The real-world applications are wide-ranging and crucial. Understanding how enzymes kick-start oxygen production when added to hydrogen peroxide is important for medical and industrial applications, as well as for environmental and biotech scenarios. Students learned how this information can be applied to everything from wound cleaning and oxygen therapy to wastewater treatment, and food and clothing production.
