Tuesday, March 8, 2016

John Skinner ADI Activity

Based on the TCAP-EOC exam for biology, I created an ADI activity that requires students to “Identify positive tests for carbohydrates, lipids, and proteins” (Performance Indicator 3210.1.4).

Step 1: Identification of the Task

In this step, I would first introduce the topics that we will need to utilize in our ADI activity. By this point, students should have an understanding of the different roles of carbohydrates, lipids, and proteins, as well as basic structural differences between these molecules. However, students will not yet know that we can test for these molecules in given samples using a variety of reagents. Thus, the introduction will describe the functions of these reagents, and then the students will be given a related investigative task.

Introduction: This would provide a quick review of the differences between carbohydrates, lipids, and proteins; discuss the three different reagents (Benedict’s Solution for carbohydrates, Biuret Reagent for proteins, and Sudan IV test for lipids), and the colors associated with positive and negative test results (for Benedict’s Solution, positive is orange/red and negative is blue; for Biuret Reagent, positive is purple and negative is blue; for Sudan IV, positive is the layer dyed red).

Problem: Mr. Turner is lactose-intolerant and a slight allergy to casein. Mr. Turner hasn’t been feeling well after attending a dinner party last night; however, he doesn’t know which of the four courses made him sick. Test four samples of food that was served last at the dinner party, and decide which course Mr. Turner should avoid in the future.

Step 2: The Generation of Data

For this step, students would be provided with the four different samples of food and test each of the different samples for carbohydrates, lipids, and proteins. Instructions will be provided on how much of each solution to use, and a variety of materials will be provided so that students can come up with their own methods for testing samples. They should consider how specific their procedures need to be, how reproducible what their data table should look like. The students should be looking for the sample that contains proteins and carbohydrates.

Step 3: The Production of a Tentative Argument

Students will use whiteboards to analyze and represent their data, discover what argument they are trying to make with regards to the samples, and determine their rationale for which sample Mr. Turner should avoid in the future. Students will need to correctly label casein and lactose and decide what tests will prove the presence of sugar and protein. 

Step 4: The Interactive Argumentation Session

Groups will explain and argue for their reasoning, learn alternatives, and assess the assumptions that other students are making with respect to the data. Students are also given the opportunity to revise their explanations based on peer feedback, if needed.

Step 5: The Creation of a Written Investigation Report

This step requires students to analyze what they were attempting to explain, what they are arguing, and their rationale for the argument they are making based on evidence.

Step 6: The Double-Blind Peer Review

Students will be provided with a specific rubric for assessing the written reports of their peers. This step also allows students to analyze what types of arguments are considered “valid” for explaining Mr. Turner’s illness.

Step 7: Revision

Step 8: Reflective Round-Table Discussion

The class will come together for a large group discussion about the ADI activity. Perhaps we will be able to draw from multiple models of food testing and come up with a group consensus regarding what processes are the most effective for testing for macromolecules in different unknown food samples. 

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