Identifying Organic Compounds in the Lab (Day 2 of 5)

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Students will be able to identify proteins, carbohydrates, saccharides, and lipids in the lab.

Big Idea

Students will be able to identify proteins, carbohydrates, saccharides, and lipids in the lab. Big Idea Get your students acquainted with organic compounds in their everyday lives using this engaging lab activity!

Notes for the Teacher

Every biology class utilizes an organic compound identification lab;  for me, this is one of the best.  By slowing down to introduce the lab equipment and safety as a separate lesson rather than a quick reminder at the start of the lab procure day, we engage student curiosity and allow them to fully digest the many complex test procedures they will be following.  

Adding in a student choice day engages students and makes things more personal for them which creates a very positive, collaborative, and inquiry based lesson day where we work together to figure out how to work with our diverse samples and asses the accuracy of our results.  And finally, giving students an opportunity to share out their original data as a class allows them to critically compare and analyze data against their prior knowledge and come up with interesting questions they'd like to investigate in the future.

The lab is broken up into a five day series:

During Day 1, students complete a pre-lab activity and explore the equipment, procedures, and safety guidelines for the series. Standards: W.9-10.1, SL.9-10.1, SP1, SP3, SP4, SP8, XC-SF-HS-2

On Day 2, students focus on the lipid and saccharide tests for five samples.  Standards: SL.9-10.1, SP1, SP3, SP4, SP8, XC-SF-HS-2

During Day 3, students focus on the protein and starch tests for five samples and brainstorm their own group samples to bring in for testing.  Standards: SL.9-10.1, SP1, SP3, SP4, SP8, XC-SF-HS-2 

During Day 4, student groups work to test their own five samples.  Standards: SL.9-10.1, SP1, SP3, SP4, SP8, XC-SF-HS-2 

And on Day 5, we come back together as a large group to assess our lab work results and review the major concepts of the series.  Standards: W.9-10.1, SL.9-10.1, SP1, SP3, SP4, SP8, XC-SF-HS-2

The Classroom Flow: Saccharide and Carbohydrate Testing

40 minutes

1.  Ask students to take out their lab document and turn to page three which outlines test procedures for each organic compound.  At this point, students will have made their predictions for each substance in their data table and summarized the role of each indicator on page one of their lab document.

2.  Announce that today they will be focusing on the first two tests for saccharides and lipids.  

3.  Point out their lab materials and review basic safety, see powerpoint slides.  

4.  Remind students that their job is to compare their data to their predictions and discuss them in preparation for their collaborative lab report before letting them get to work!

  • Note: You may find that some groups finish these two tests early and ready to move on to the starch and protein tests and if so, you can determine if you would like them to move on or if their group needs to dig a bit deeper into the data they collected during this lab session.

5.  As students work, circulate, observe, and support groups as needed.  See the organic chemistry lab tips and tricks document for ideas!

6. If students feel comfortable about their results and you see that they are winding down, announce that they can begin to brainstorm what items they might each want to bring in on Day 4. If that feels like a bit of an attention/focus stretch for any group, suggest that they work through some of their analysis questions or continue to share out their data collection results with their lab team.  

  • Note  I found that the pacing of this lab worked really well with my students.  There was enough time for students to proceed at their own pace without feeling stressed or rushed as they performed their lab procedures and made sense of their data and at the same time, student groups are not sitting idly by with no on-task goals to work toward as a group.   

7.  Check out this data table student sample outlining one student group's results for this day's tests.

  • Note:  This work was representative of all of the groups' work turned in at the completion of this lab activity and group lab report discussion/writing session.  Lab reports were expected to be typed and included their pre-lab work (procedure, reagents, and hypotheses) and the data they collected and recorded as a group.  The data collection for the tests students worked with today was relatively straightforward; today's challenge was more about how to use the equipment and work with multi-step procedures while performing their lab work in a safe and efficient manner as a team.  

The Classroom Flow: Clean Up and Preparation

10 minutes

1.  Announce that it is time to begin to clean up.  The general expectation is that students leave their lab stations looking exactly like they found them at the beginning of class--clean, dry, organized, and with all of the necessary materials.  This simple set of directions helps to focus the kids on a very clear set of expectations.  

2.  Remind students that tomorrow they will continue to work with their substances in the starch and protein tests.

And now on to Day 3!