Enzyme Function: Exploring the Concept of Denaturation with Pineapples (Day 1 of 2)

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Objective

Students will be able to collect and analyze data in this classic enzyme denaturation experiment.

Big Idea

Get your students thinking about enzyme function and all the ways it can be affected in this classic pineapple lab!

Notes for the Teacher

This lesson series explores enzyme activity using a classic bromelin/pineapple set up.  On Day 1, students perform the lab procedure and document their data.  On Day 2, we work together as a class to analyze our results and summarize our findings.  I like this experiment because it isn't an easy reach for students conceptually and our collaborative conversation requires focus and close attention by the students in order to follow the data to its conclusion.  Anytime we get to practice this skill at a high level in class, I am very happy to do!  

Day 1 connections to the standards:  SL.9-10.1RST.9-10.3SP3, SP8, SP4SP7XC-SF-LE-1

Day 2 connections to the standards: W.9-10.1eSL.9-10.1SP4, SP8, SP7XC-SF-LE-1

You will notice that the first day of the lab is very student centered--the directions for the lab procedure are explicit and easy for them to follow, allowing you time to monitor for safety and materials handling, as well as observe how individual groups are working together as a team and intervening/supporting as necessary.  The second day of the lab is when you as the teacher direct the flow of discussion that enables deeper understanding and connection by the students, linking the concept of enzymes and how they work within specific temperature and other parameters.  

For me, I am finding that enzymatic action is something that we revisit throughout the year and each time, student depth of comprehension grows.  This is the first activity in that spiral of conceptual understanding.  I like that the first day involves easy technique that students enjoy engaging in with everyday materials like pineapple that look and smell good.  That may sound silly, but anything the connects science to student life, experiences, and strengths is a subtle strategy I intentionally employ in order to get each student to consider science as something relatable, doable, and relevant to them as people and citizens.

The Classroom Flow: Lab Set Up and Preparation

20 minutes

1.  Pass out the enzyme denaturation lab document for today's activity.

2.  Ask students to read the two introductory paragraphs to themselves.

3.  Tell students to turn to their lab group partners and discuss the following two prompts:

What do we know about enzymes and what they do?

What is bromelin?  What does it do?

4.  Popcorn out answers for a brief review of enzyme activity and a check to ensure students understand the lab activity materials background.  

5.  Ask students to look at the lab procedure while you point out the materials: canned and frozen pineapple samples, fresh and boiled pineapple samples, and related lab equipment available at the front of the room.

6.  Allow students to popcorn out the different steps as you question them about their familiarity with the general procedure, using prompts like:

How many test tubes will you use?  What is in each one?

How much gelatin do you need?  

  • Note: All of the answers to the prompts listed in this section are in the introductory paragraph and the procedure on the front page of the lab document so it is easy to redirect students if they are off track.  If you have an overhead projector/document camera, you can highlight the relevant sentences/sections as you discuss the prompts.

The Classroom Flow: Experimental Procedure and Data Collection

20 minutes

1.  Have students turn over their lab document and make predictions about their data by discussing with their lab group their ideas before writing them down.  Remind students that these hypotheses are not going to be graded as right or wrong, just that they made an educated guess for comparison.

2.  Once student groups have completed this step, ask students determine roles for this lab:

Data recorder:  This is the student responsible for recording data and ensuring that each lab team member receives it for their own analysis

Materials collector/clean up: This student is responsible for ensuring that all materials are available at the lab table when needed and that they are returned to the classroom supply area before the lab session is over

Lab project manager: This student ensures that the procedure is understood by all, checks in to make sure each team member is on task with their specific job, and checks in with the teacher when questions come up for the team

Experimenters (2): These team members are the students who perform the lab experimental procedure and work directly with the materials.

  • Note:  In my classes, I offer role options to support group functionality but if groups are comfortable taking on flexible leadership roles throughout the lab, that is what I would ideally like to see and therefore encourage and monitor.  

3.  Direct students to get to their lab tables for set up and begin their experiment.

  • Note:  I tend to take on the role of gelatin pourer as it can be quite warm.  In some years, I have put out ice baths for students to use to get immediate results but I typically prefer to leave the test tubes in the refrigerator over night so as to avoid any confusion about results due to the tubes not having a low enough temperature/enough time to gel correctly or have condensation form in the tube, confusing students about the solid/liquid nature of the gelatin.  

4.  Remind students to use their lab time wisely and when there is downtime as they wait for their tubes to gel, to begin looking at and discussing the discussion questions on the back of the lab document.

5.  The student work sample shows a typical student data table and answers to the analysis questions.  This student has a general idea of a what a control is for and what denaturation is, but I can see we will need to discuss both concepts a bit more to make stronger connections between temperature and enzyme activity and to help the student determine what would be the most appropriate control for their own experimental design/extension (question #6).  

The Classroom Flow: Clean up and Connection to Tomorrow's Work

10 minutes

1.  Ten minutes before class ends, instruct students to begin their clean up procedure and return lab materials to the front of the room

2.  Remind students that we will be going through our lab analysis questions tomorrow as a team.

On to Day 2!