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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

Comments

Erin Hall's picture

peanut butter allergies

Does anyone have any suggestions for a peanut butter substitute? I have a few students with peanut allergies.

iwaldron's picture

Possible substitutes for peanut butter

Possible substitutes include sunflower seed butter, pumpkin seed butter, soy nut butter, and tahini (made from sesame seeds). If you are allowed to use nut butters, consider almond butter, pecan butter, etc. Additional information is available at https://www.foodsharkmarfa.com/peanut-butter-substitutes/ and https://www.thekitchn.com/5-nut-free-alternatives-to-peanut-butter-222921. If you do try one of these alternative butters, please pilot test it before using in your classroom. Also, please let us know how it works out, so we can include this information in our Teacher Preparation Notes.

Thank you,

Ingrid

Jeff's picture

Glucose

Can this lab be done without the glucose and can real egg whites substitute powdered?

iwaldron's picture

Proposed Changes in Procedure

I think that the procedure is likely to work alright with real egg whites instead of powdered egg whites, but I don't know and I strongly recommend that you pilot test this change. Note that you will need to include the egg white in the liquid evidence instead of the dry evidence (see Teacher Preparation Notes page 3).

If you omit the glucose, you will need to make multiple changes in the Student Handout and it may become difficult to make the mystery work out in a good way. You can purchase glucose as dextrose, so perhaps that will make it easier for you to include glucose as described in the Student Handout.

Ingrid

Jacquelyn Wilson's picture

THANK YOU! And question re: Macromolecules Lab/Jerell's iPod

Thank you so much for the amazing resources you offer. I just began teaching this year, after many years as an education director for a non-profit. It is so wonderful to find resources that are as detailed, rigorous as yours. I also appreciate that so many of your resources use data! (The non profit I worked for supported the science of the Hubbard Brook Ecosystem Study and I too, tried to take data and turn it into something useful for teachers.... no easy task. I was excited to see that you used data from HB in one of the ecology activities that have students think about energy flow through an ecosystem.) I use your resources often- THANK YOU.

I'm also writing with a question about the activity: "Who took Jerell's iPod: An Organic Compound Mystery." The procedure states that students will test dry and liquid substances, and that it's important to keep and test them separately. I don't understand what the liquid samples might be? All of the ingredients in the lunches belonging to the various "possible suspects" seem to contain only dry ingredients. Can you please clarify? Thanks so much!

Jacquelyn Wilson

iwaldron's picture

Macromolecules Lab/Jerell's iPod

Thank you for your appreciation!

In the Student Handout on the bottom of page 5, the bottom two rows of the table refer to the dry and liquid evidence from the scene of the crime. On the third page of the Teacher Preparation Notes, the second table describes how to prepare the dry and liquid evidence, depending on which worker you want to identify as guilty of taking the iPod. (If you teach multiple classes, you may want to rotate who is guilty in different classes.)

Good luck!

Ingrid

Jacquelyn Wilson's picture

Thank you!

Thanks so much for clearing that up- I get it now :)

Serendip Visitor's picture

Simply Tested 8 Food Items

I placed 8 cups of food at each station:
1. mashed up beans 2. Nacho Cheese Sauce 3. Torn Bits of Tortilla 4. Fat Free Yogurt 5. Torn bits of Toast 6. Butter
7. Strawberry Jelly 8. Broken Pretzels

Made a new data table for the students to record their test results of the 8 food items, and had the students glue it over the former on page 5 of the handout.

Data table on page 6 - the students were able to use the information from data table on page 5 to show + or - for the food items consumed in the break room by each suspect.

I told the students at the end of the lab that I tested the evidence and the results were..... then they simply matched up to their findings and they were able to easily determine the culprit.

This is how the lab made sense to me.

iwaldron's picture

Thank you

Thank you for your helpful suggestions,

Ingrid

A Bigler's picture

Out-of-date link

Thank you so much for this lab! I really hope my students have fun with it. One question, the link to the glucose test strips is out of data/cannot be found. I would rather do the strips than a Benedict's test, but I want to make sure I am getting the right test strip. It's too late for me to order anything online, so I was hoping to pick something up locally. Would the ketone urinalysis work? or does it need to explicitly say it tests for glucose in urine?

Thank you!

Serendip Visitor's picture

glucose strips

try Carolina science supply for strips...100 for 19.95

1bassoon's picture

Glucose Strips

I've used the following from Amazon with great success:
Neo-Sci Glucose Food Test Strips
(link too long to paste here)

They are under $15 for 50. HTH!

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.

Thanks.

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

Biology

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.

Thanks,

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?

Thanks.

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,

Ingrid

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

Hi,
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.

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