Enzymes Help Us Digest Food

In the hands-on activity, Enzymes Help Us Digest Food, experiments with the enzyme lactase and discussion questions help students to learn about enzyme function, enzyme specificity, and the molecular basis for lactose intolerance. Students also learn about the scientific method by interpreting evidence to test hypotheses and designing the second and third experiments to answer specific scientific questions about lactase. An alternative version of the Student Handout which gives specific instructions for all three of the experiments is provided as an attachment below.

Download Student Handout: PDF format or Word format

Download Teacher Preparation Notes: PDF format or Word format

We invite comments on this Hands-On Activity and the accompanying Teacher Preparation Notes, including suggestions for other teachers who are planning to use the activity, useful preparatory or follow-up activities, additional resources or any questions you have related to the activity, or a brief description of any problem you might have encountered. If you have a relevant Word document you would like to have posted on this comments page, such as a version of the protocol you have used in your classroom, or if you would prefer to send your comments or questions in a private message, please write Ingrid Waldron at iwaldron@sas.upenn.edu.

See also a complete list of activities:
Hands-on Activities for Teaching Biology to High School and Middle School Students

EnzymeSHO.doc639.5 KB


Anna's picture

That is nice. Thanks for your

That is nice. Thanks for your explanation

Serendip Visitor's picture

enzymes help us digest food instructions for all three parts

I wanted to know if you can send the instructions for all three parts of the experiment "Enzymes Help Us Digest Food"?
Thank you, Carla Lowden

iwaldron's picture

instructions for all three parts

The procedures for all three experiments are described in the attachment available above.


iwaldron's picture

Using Lactaid Pills from the Drugstore

Tim Best reports success in using Lactaid pills instead of purchasing lactase enzyme.

"I've done 2 parts of the lab recently, and the store-bought lactase seems to work fine. I called Fisher Scientific, and found that depending on the batch the lactase they sell has somewhere between 12000-18000 lactase units per gram. The lactase from CVS is labelled as having 9000 units per pill, so I've just been dissolving 2 pills in 50mL of water, and having each group use 1mL of this solution. The glucose test strips are definitely indicating the presence of glucose when they should, although we've found that it does take more like 5-6 minutes as opposed to 3."

I welcome any additional feedback about this or any other suggestions.
iwaldron's picture

August 2012 revision

The main change in the new version of the Student Handout for this activity is that in the current version students design the second and third experiments. This will help to increase student understanding of the scientific method. If you would prefer to have explicit instructions for all three of the experiments, these are provided in an alternative version of the Student Handout. In addition, the Teacher Preparation Notes have been somewhat expanded and clarified.

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