This investigative case module was prepared as part of a BioQUEST faculty development workshop. The cases, resources, and implementation strategies were developed by participants for use with their own students. We invite you to adopt and adapt the following materials.

The BioQUEST Curriculum Consortium is committed to the reform of undergraduate biology instruction through an emphasis on engaging students in realistic scientific practices. This approach is sometimes characterized as an inquiry driven approach and is captured in BioQUEST's three P's (problem-posing, problem-solving, and peer-persuasion). As part of this workshop groups of faculty were encouraged to initiate innovative curricular projects. We are sharing these works in progress in the hope that they will stimulate further exploration, collaboration and development. Please see the following links for additional information:

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Investigative Cases
The Case: As the Stomach Turns

I opened the door of a nearby health food and vitamin store. “Why had I come here?”, I thought. I remembered how much my stomach would hurt -- event though didn’t happen all the time.” Smells of incense filled the air as I moved to a large shelf labeled, “DIGESTIVE AIDS”

A young woman approached me and asked, “Need help?”

I told her about my digestive problems. Hoping that she would not give me that your such an old lady look.

I asked, “Will these enzymes really help?”

She quickly said yes and explained how these enzymes capsules would provide extra amylase and other important digestive enzymes.

“In fact,” she said, “even younger people have digestive problems such as reflux and ulcers that these things can help with.”

“You know”, she added “as we age our ability to produce enzymes decreases rapidly. By the age of 50 you can only produce 50% of the amount of enzymes needed. But even younger people need these enzymes.”

“Umm,” I thought. “I was already 51, no doubt I was already enzyme challenged. But if they would help the cost would be worth it.” I still had a lot of questions. “What about some information about these enzymes?” I asked. She quickly pointed toward a rack containing brochures.

Case Author:
Linda Crow Montgomery College

How to find out answers?

Lab experiments
Visits to Health Food Stores

Case Analysis

  • Can digestive enzymes be added to your own digestive system?
  • Are they effective? How will we know?
  • Is information at the health food store unbiased?
  • How do enzymes work?
  • How does the digestive system use enzymes?
  • How does the digestive system work?
  1. What are the parts, structure and function of the digestive system?
  2. What is digestion? Where does digestion occur?
  3. What enzymes are found in the digestive system? What do they do?
  4. What enzymes are in those digestive aids?
  5. Are they the same as our own digestive enzymes?
  6. Will they be effective?
  7. Are some sources of information more biased than others? How can I tell the difference?

Option: Include a know / need to know chart like the one below:

What do you know?
What do you need to know?

Learning Goals


  1. Label a diagram of the digestive system with major parts
  2. Define digestion both mechanical and chemical and indicate where these types occur.
  3. Define operationally acid, base and indicator.
  4. Construct graph depicting the effects of pH on enzyme activity and comparison of amylases from different sources (pills vs natural).
  5. Describe operationally how an enzyme works and why it is needed in the digestive process.
  6. Locate and identify the components of digestive enzymes commonly sold.
  7. Identify enzymes by looking at names of ingredients (ase rule)
  8. Compare the structure of the same enzyme from different sources using computer modeling programs
  9. Identify sources as either objective or biased and provide a rationale for the decision.



Investigations and Activities

Acid, Base and Indicator Lab.
See and Crow, 2001.

Amylase lab using pH differences. Be sure to have pH solutions that mirror digestive tract (stomach and small intestine). Use chemical amylase.

Compare amylase activity of digestive enzymes with chemical amylase. Can it really change starch into sugar? Beano and Lactaid Lab – Are they effective? Goals 3, 4

Hydrogen Peroxidase Lab – Lab to answer questions concerning how enzymes work and why they are needed.

Students either visit store or search internet for ingredient lists for digestive aids. Need at least two showing ingredients and amounts. Class data is accumulated on an Excel sheet and then students analyze for any differences in content and quantities.
Goal 6

Students use models, ADAM and texts to complete anatomy worksheet on digestive system.They view the Home Depot demonstration model of digestion. Goals 1 and 2

Examine models using computer programs of different amylases – Goal 8

Students are sent to different http sites and are asked to evaluate the objectivity of the information. Goal 9


Resources and Crow, 2001.

Various biology and anatomy and physiology text books

Torso Models, Home Depot Model

ADAM Interactive

Students will usually obtain additional references or resources
to help answer or explore their questions.

Special Data Items

1. stomach1.gif
2. stomach2.gif
3. stomach3.jpg
4. stomach4.gif
5. stomach5.gif
6. stomach6.gif
7. stomach7.gif
8. stomach8.gif


Student Products

  • Graphs and interpretations of enzyme labs
  • Evaluation of Sites
  • Analysis of Ingredients of Supplements from class data

Assessment and Evaluation Plan

  • 10% Lab Performance Assessment on Acids, Bases and Indicators
    Objective 3
  • 60% Content Test on structure and function of digestive system
    Objectives 1,2, and 5
  • 5% Performance Assessment on Objectivity of Sites
  • 25% Graphs and Written Interpretations for Labs Objectives 4 and Ingredient Analysis



Course name:
Introductory Biology
Likely sequence in syllabus:
Digestion Anatomy and Physiology
Time during term:
One week
Classroom, Field
Students in course:
Majors, non-Majors
Collaborative elements:
Group work, presentation
Additional notes:



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