Biology and Education: Enzyme Functions and Properties

Title: An Introduction to Biology Lab: Enzyme Functions and Properties
Discipline(s) or Field(s): Biology, Chemistry, Health, Medicine, Education
Authors: Kama Almasi, Lisa Bardon, Kurt Freund, Isabelle Girard, Eric Singsaas, University of Wisconsin-Stevens Point
Submission Date: August 15, 2007

Student Learning Goals: We have two different types of goals we hope to address in this lesson.  We have lesson-specific goals and we have a few goals that we hope to address throughout the course.  In our course goals, we emphasize improving our students’ comprehension of scientific concepts.  In the lesson goals, we focus on concepts relevant to how enzymes work.

General Biology Course Goals
Students will be able to:

1. Express biological processes using mathematical, graphical, and visual form with figures.
2. Improve oral and written communication skills
3. Enhance collaboration skills
4. Develop the following basic laboratory techniques: following a protocol, pipeting, measure  volume, timing, data recording, and graphing.
5. Develop the parts of a scientific report: introduction, methods, results, and discussion.

Enzyme Function Lesson Goals
Students will be able to:

1. Formulate a scientific question in terms of a testable hypothesis
2. Discover the importance of enzymes in cellular metabolism
3. Describe enzyme roles and how they relate to other biological aspects.  Example: How enzyme response to temperature determines where organisms can live on earth.
4. Recognize and interpret nonlinear responses from their data
5. Identify and correct misconceptions about biological functions, including: enzymes add energy, enzymes are “alive”, enzymes can “decide”, enzyme reactions are “on/off”.
6. Define and apply the following vocabulary: enzyme, product, optimization, catalyst, protein, substrate, saturation, rate, and equilibrium.

Findings and Discussion: The lesson was a (3-hr) laboratory exercise on enzyme reactions. Students used simple materials tomeasure the rate of oxygen production from hydrogen peroxide in the presence of catalase, extracted from potatoes, which catalyzes this reaction. Once the students learned the basic measurement, they were asked to vary the concentration of enzyme, concentration of hydrogen peroxide, the temperature, and add an inhibitor. Students were asked to graph their results (e.g., relationship between temperature and oxygen production rate) for each experiment and to answer questions about the experiment, procedure, and results at each stage of the experiment. At the end of class, groups were asked to share their results with the class and discuss any differences between their results and other groups’ results.

As a result of information we gained during initial observation of the lesson, we substantially revised the protocol and lesson plan. In observations during labs using the revised protocol, we observed substantial improvements in students engagement with the material: student use of terminology increased, discussion of the topic material increased, student-instructor interaction increased, and attention to procedural details decreased.

The process of lesson study demonstrated to us, in a very dramatic way, how ineffective we are in assessing our lessons while we are teaching them. Although we were familiar with the end results of the unimproved lesson, we had not been able to determine the source of difficulties. Only when we were allowed to serve as observers – and not as instructors – were we able to devote the attention needed to listen to student conversations and understand the challenges. Afterwards, it was surprisingly easy in our group to generate ideas to address the inadequacies of our design.

The practice of teaching without observation or reflection now seems absolutely absurd. However, we have all agreed that our current teaching loads prevent us from applying our lessons from lesson study in any practical way.