Who Took Jerell’s iPod? -- An Organic Compound Mystery

In the lab, Who Took Jerell’s iPod? -- An Organic Compound Mystery, students learn how to test for triglycerides, glucose, starch, and protein and then use these tests to solve a mystery. The activity reinforces students understanding of the biological functions and food sources of these different types of organic compounds.

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


Serendip Visitor's picture

marking this lab

Hello and thank you for sharing this version of a macromolecules lab. I have always done one with my first term biology students, but this one is much more interesting and creative than others I have seen and used. I would like to adopt it for my classes, but I am concerned about how to mark it efficiently and effectively. There are a lot of questions throughout the activity, and it would take a great deal of time to mark 60 plus student submissions of this lab thoroughly and with constructive feedback. Do you have a fast track method or advice with the marking?

iwaldron's picture

Using different questions for formative and summative assessment

I would suggest that, for each question or group of questions, you think about whether you want to use this question for:

    – writing answers that will be graded and discussed

    – writing answers that will be checked off and discussed, but not graded

    – writing answers that will be discussed, but not checked off or graded

    – discussion without necessarily writing answers.

For example, you might want to grade only questions 1-3 on page 4 of the Student Handout and questions 1-2 on pages 7-8.

Discussions of the questions as you work your way through the activity can serve as formative assessment and provide the opportunity to give constructive feedback to student responses and should also help to keep the students engaged. Grading the suggested questions could serve as summative assessment. I hope you can adapt this general approach to work well in your classroom. 

iwaldron's picture

November 2012 revision

This revision has incorporated some small but important methodological improvements, including the recognition that pretzels have significant amounts of protein which can be detected if the pretzel is crushed into fine crumbs and tested with Biuret reagent. 

iwaldron's picture

August 2012 revisions

The revisions of the Student Handout include clarification of the instructions and some improvements in the questions, including new questions at the end of Part I to facilitate the transition to Part II. In the revised Teacher Preparation Notes, we have clarified and expanded the instructions for carrying out this activity and we have added suggestions for substituting a student-designed investigation as Part II of this activity.

christie melanson's picture

Protein test

I love this lab and am trying it for the first time wit my students, but I have a few questions. What if you can't get the white beans and the yogurt to test positive for protein? And, why does the gelatin test positive for protein? It's been a while since I've been on the Bio side of the tracks.


iwaldron's picture

testing for protein

We are not sure why you are having trouble getting beans and yogurt to test positive for protein, but one possibility is that Biuret solution may become less sensitive over time, so we recommend using fresh Biuret solution. Gelatin tests positive for protein because it is a mixture of proteins and peptides derived from collagen, a protein that is abundant in bones, connective tissue and skin.

J. Flanagan's picture


I like to use this lab but wish the teacher instructions were a little more detailed.

iwaldron's picture

Requests for information and clarification invited

I will be happy to prepare more detailed teacher instructions after I finish my spring teaching. In the meantime, it will be helpful if you and others would let me know any questions you have, additional information you would like to have, or specific aspects of the instructions that you would like to have clarified.


Ingrid Waldron

Candi B's picture

Question regarding Day 2

First, thank you for this lab! On Day 2, what do the students write in the data table for Henry's evidence?


iwaldron's picture

Clarification of Instructions for Day 2

For day 2, the students test the food items listed on page 5 of the Student Handout and the dry and liquid parts of Jerell’s evidence to complete the table on the bottom half of page 5 of the Student Handout.  To prepare the dry or solid evidence and the liquid evidence, consult the instructions on the top of page 2 of the Teacher Preparation Notes.  You can pick whichever worker you want to identify as the one who left the evidence.  For the dry or solid evidence, combine starch and protein for José’s lunch/snack or glucose and protein for Ashley's lunch/snack or glucose and starch for Bruce's lunch/snack or just starch for Kiara’s snack. Follow the instructions in the table to know whether to have the liquid evidence be oil or water. Then, have your students test the dry and liquid evidence samples for glucose, starch, protein and lipid.

You will notice that our Teacher Preparation Notes recommend having different evidence samples for different student groups to test, so different groups can't just assume they will get the same results as other groups.  However, if you prefer, it is fine to give all your groups the same dry and liquid evidence samples.

Please let me know if you have any additional questions,


Ms. B's picture

A teacher on my team tried a

A teacher on my team tried a different lab and it did not go well. I found this lab before the rest of the team had to suffer through the other lab. Thanks so much!!!

Ingrid Waldron's picture

October, 2010 revision

The October, 2010 updated versions of the student handout and teacher preparation notes clarify the instructions for preparation and testing of the food and evidence samples on day 2.

iwaldron's picture

clarification of instructions to prepare evidence samples

You can see from the top of page 2 of the Teacher Preparation Notes that each lunch/snack is represented by a pair of samples, one sample of solid evidence and another sample of liquid evidence. For example, for the bean burrito with cheese the solid evidence will include starch and protein (e.g. cornstarch mixed with dried egg whites or gelatin) and the liquid evidence will be oil.

Krishna Millsapp's picture

So glad i read the

So glad i read the clarification.. I could not figure it out how to create evidence with out using the real food items. Thanks again!!!

Serendip Visitor's picture

Samples Further Clarification

From what I gather - we will be using the materials from Day 1 of the lab to make up the different samples of liquid and solid evidence for the Day 2 part of the lab. So, my question is - why do you need pretzels, canned white beans, butter, jelly and yogurt if they are all going to be simulated by Day 1's materials? Also, do you have any suggestions for what the mystery evidence should be or can I just pick any combination that I prefer? Thanks for your help!
~ J

iwaldron's picture

testing macromolecule composition of food and samples

The students are testing the food to see which macromolecules each type of food contains and then testing the evidence to try and match the macromolecule composition of the evidence to the food eaten by the suspects. To prepare the evidence, please use the instructions and table on the top of page 2 of the Teacher Preparation Notes. The solid and liquid evidence need to be prepared separately, each presented in small sample jars labeled with the appropriate letter as indicated in the table.

Serendip Visitor's picture

Keep up the great work -

Keep up the great work - these are wonderful labs (or modifications on old labs) in one organized, succinct location. Thanks so very much!!!

Anonymous's picture

Request for shortened

Request for shortened students notes

iwaldron's picture

shortened version of student handout available above

The shortened student handouts are available in the two files listed above as JerrellIpod1 and 2 (under the heading Attachment).

iwaldron's picture

shortened version of student handout available in attachments

The attachments shown provide a shortened, reorganized, two-part version of the student handout.

Post new comment

The content of this field is kept private and will not be shown publicly.