Final Product: Students will prepare a written report detailing the experimental procedure and their results. Cross-Disciplinary Standards Assessed

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1 TCCRI College Readiness Assignments Macromolecule Mixes! Overview Description In this assignment, students will compare and contrast different macromolecules. In addition, students will identify the macromolecules in a variety of substances using various indicators. Final Product: Students will prepare a written report detailing the experimental procedure and their results. Course Biology Task Level Grade 9 12 Cross-Disciplinary Standards Assessed I. Key Cognitive Skills A.2. Construct well-reasoned arguments to explain phenomena, validate conjectures, or support positions. A.3. Gather evidence to support arguments, findings, or lines of reasoning. A.4. Support or modify claims based on the results of an inquiry. C.1. Analyze a situation to identify a problem to be solved. C.3. Collect evidence and data systematically and directly relate to solving a problem. C.5. Synthesize and organize information effectively. D.1. Self-monitor learning needs and seek assistance when needed. D.3. Present analyzed data and communicate findings in a variety of formats. E.1. Work independently. E.2. Work collaboratively. Science Standards Assessed I. Nature of Science: Scientific Ways of Learning and Thinking A.4. Rely on reproducible observations of empirical evidence when constructing, analyzing, and evaluating explanations of natural events and processes. Texas College and Career Readiness Initiative 1

2 Macromolecule Mixes! B.1. Design and conduct scientific investigations in which hypotheses are formulated and tested. C.1. Collaborate on joint projects. C.2. Understand and apply safe procedures in the laboratory and field, including chemical, electrical, and fire safety and safe handling of live or preserved organisms. C.3. Demonstrate skill in the safe use of a wide variety of apparatuses, equipment, techniques, and procedures. D.3. Demonstrate appropriate use of a wide variety of apparatuses, equipment, techniques, and procedures for collecting quantitative and qualitative data. II. Foundation Skills: Scientific Applications of Communication B.2. Set up apparatuses, carry out procedures, and collect specified data from a given set of appropriate instructions. C.1. Prepare and present scientific/technical information in appropriate formats for various audiences. IV. Biology Objectives B.1. Understand the major categories of biological molecules: lipids, carbohydrates, proteins, and nucleic acids. Students will: Distinguish between qualitative and quantitative analysis. Know four main types of organic macromolecules found in living organisms. Name the indicators used to test for protein, carbohydrates, and lipids, and distinguish between a positive and negative result for each. Engage in safe laboratory practices while experimenting with chemicals. Understand the purpose of a control in an experiment. Present the results of a scientific investigation in an appropriately formatted written report. Preparation Read the and the Student Notes. Prepare student copies of the Student Notes pages and Introduction to Macromolecules, Demonstrating the Presence of Carbohydrates, Proteins, and Fats, and Data Tables handouts. Arrange student access to the following materials: Texas College and Career Readiness Initiative 2

3 Macromolecule Mixes! One 600-mL beaker (to serve as water bath for the Benedict test) 11 test tubes Test tube rack Test tube holder Test tube brush (found on sink) Hot plate (one at each of the four lab tables placed around the room) Safety goggles (at lab tables) Lab aprons Sharpie marker 3 ml of a 10% gelatin solution 3 ml of a 10% sugar solution 3 ml of a 10% starch solution Vegetable shortening Dropper bottle of Benedictʼs solution Dropper bottle of Biuret reagents Dropper bottle of Lugolʼs Iodine solution 11 squares of brown paper Distilled water Food samples: egg white, egg yolk, apple juice, vegetable oil, spinach, potato, whole milk, honey, and two unknowns Prior Knowledge Students need experience working with laboratory equipment in a safe and effective way. Students should also be familiar with the different types of macromolecules and how they benefit living organisms. Vocabulary Carbohydrate Control Disaccharide (sugar) Indicator Lipid (fat) Macromolecule Texas College and Career Readiness Initiative 3

4 Macromolecule Mixes! Monosaccharide (sugar) Polymer Polysaccharide (starch) Protein Qualitative Quantitative Time Frame This assignment will require approximately six days to complete. The timeline may need adjusted to different class-period lengths. Example for 90-minute periods: Day 1: Introduction of activity using a vocabulary review and research to find examples of macromolecules found in living systems. Day 2: Lab time to review safety rules and materials needed for the activity. Four areas in the lab room should be set up with materials and equipment to conduct the tests. Before the students complete any of the tests, the instructor should demonstrate the proper safety procedures to be used to heat test tubes, handle hot objects, etc. Day 3: Continue with lab; record results in data tables and meet together as a class to review results and discuss them. Emphasize the function of the control in the experiment. Day 4: Students will be given unknown solutions to identify as a protein, sugar, starch, or lipid. They will use the materials at the four tables to conduct their experiments. Once the students have identified their unknown solutions, they will complete the data table. Days 5 6: Student lab groups will present their results. Texas College and Career Readiness Initiative 4

5 Macromolecule Mixes! Instructional Plan Getting Started CCRS Performance Expectations Cross-Disciplinary Standards: I. Key Cognitive Skills C.1. Analyze a situation to identify a problem to be solved. E.1. Work independently. Science Standards: I. Nature of Science: Scientific Ways of Learning and Thinking C.2. Understand and apply safe procedures in the laboratory and field, including chemical, electrical, and fire safety and safe handling of live or preserved organisms. IV. Biology B.1. Understand the major categories of biological molecules: lipids, carbohydrates, proteins, and nucleic acids. Learning Objectives Students will: Distinguish between qualitative and quantitative analysis. Know four main types of organic macromolecules found in living organisms. Name the indicators used to test for protein, carbohydrates, and lipids, and distinguish between a positive and negative result for each. Procedure 1. Introduce the activity by discussing the four main macromolecules that make up living things (carbohydrates, proteins, lipids, and nucleic acids). For homework, have students complete the Introduction to Macromolecules handout. 2. Prompt a class discussion of the difference between qualitative and quantitative measurements. 3. Instruct students as to where the needed materials are located and how to use them safely. Establish standards for student use of unknown substances. 4. Divide the class into pairs. 5. Remind students to keep their standards until the completion of the lab. Texas College and Career Readiness Initiative 5

6 Macromolecule Mixes! 6. Review the testing procedures for different macromolecules provided in the Demonstrating the Presence of Carbohydrates, Proteins, and Fats handout. Investigating CCRS Performance Expectations Cross-Disciplinary Standards: I. Key Cognitive Skills A.3. Gather evidence to support arguments, findings, or lines of reasoning. C.1. Analyze a situation to identify a problem to be solved. C.3. Collect evidence and data systematically and directly relate to solving a problem. D.1. Self-monitor learning needs and seek assistance when needed. E.2. Work collaboratively. Science Standards: I. Nature of Science: Scientific Ways of Learning and Thinking B.1. Design and conduct scientific investigations in which hypotheses are formulated and tested. C.1. Collaborate on joint projects C.2. Understand and apply safe procedures in the laboratory and field, including chemical, electrical, and fire safety and safe handling of live or preserved organisms C.3. Demonstrate skill in the safe use of a wide variety of apparatuses, equipment, techniques, and procedures. D.3. Demonstrate appropriate use of a wide variety of apparatuses, equipment, techniques, and procedures for collecting quantitative and qualitative data. III. Foundation Skills: Scientific Applications of Communication B.2. Set up apparatuses, carry out procedures, and collect specified data from a given set of appropriate instructions. V. Biology B.1. Understand the major categories of biological molecules: lipids, carbohydrates, proteins, and nucleic acids. Learning Objectives Students will: Know four main types of organic macromolecules found in living organisms. Texas College and Career Readiness Initiative 6

7 Macromolecule Mixes! Name the indicators used to test for protein, carbohydrates, and lipids, and distinguish between a positive and negative result for each. Engage in safe laboratory practices while experimenting with chemicals. Understand the purpose of a control in an experiment. Procedure 1. Instruct students to carry out the experiment and complete Data Tables handout. Remind students to be thoughtful with their predictions before beginning the actual tests. 2. Ensure that there is an organized flow as students move from testing station to testing station. Drawing Conclusions CCRS Performance Expectations Cross-Disciplinary Standards: I. Key Cognitive Skills A.2. Construct well-reasoned arguments to explain phenomena, validate conjectures, or support positions. A.4. Support or modify claims based on the results of an inquiry. C.5. Synthesize and organize information effectively. D.1. Self-monitor learning needs and seek assistance when needed. D.3. Present analyzed data and communicate findings in a variety of formats. E.1. Work independently. Science Standards: I. Nature of Science: Scientific Ways of Learning and Thinking A.4. Rely on reproducible observations of empirical evidence when constructing, analyzing, and evaluating explanations of natural events and processes. III. Foundation Skills: Scientific Applications of Communication C.1. Prepare and present scientific/technical information in appropriate formats for various audiences. IV. Biology B.1. Understand the major categories of biological molecules: lipids, carbohydrates, proteins, and nucleic acids. Texas College and Career Readiness Initiative 7

8 Macromolecule Mixes! Learning Objectives Students will: Know four main types of organic macromolecules found in living organisms. Name the indicators used to test for protein, carbohydrates, and lipids, and distinguish between a positive and negative result for each. Understand the purpose of a control in an experiment. Present the results of a scientific investigation in an appropriately formatted written report. Procedure 1. Instruct students to individually prepare a written report detailing their experimental design and results. 2. Provide the students with expectations for the report, such as page minimum, required sections, and necessary items to cover including: a. Identifying which types of macromolecules the unknown substances are. b. Describing the function of a control substance in the experiment. c. Describing the functions of biological molecules within a living system. Texas College and Career Readiness Initiative 8

9 Macromolecule Mixes! Scaffolding/Instructional Support The goal of scaffolding is to remove support gradually to encourage student success, independence, and self-management. The following suggestions are examples of scaffolding that can be used by instructors to meet diverse student needs while students are completing this assignment: Each lab group member should have a specific role to play in completing the activity. These roles can be monitored and adjusted by the instructor to ensure that all students get to participate. Color drawings and graphic organizers such as V-diagrams can be used to demonstrate lab results and can be assigned to students who do not feel comfortable handling lab equipment. Science Lab Reports: V-Diagram PRIOR KNOWLEDGE FOCUS QUESTION CONCLUSION HYPOTHESIS MATERIALS SAFETY GRAPHS/ CALCULATIONS PROCEDURE DATA COLLECTION Texas College and Career Readiness Initiative 9

10 Macromolecule Mixes! Solutions The solutions provided in this section are intended to clarify the problem for instructors. These solutions may not represent all possible strategies for approaching the problem or all possible solutions. It should be used for reference only. Biuret solution is used to test for proteins. When the Biuret reagent reacts with a protein, it changes color to a pink or purple. Benedictʼs solution is used to test for monosaccharides or disaccharides (sugars). When in the presence of sugars, Benedictʼs solution will change to green, yellow, or brick-red, depending on the amount of sugar present. Lugolʼs solution is used to test for polysaccharides (starches). When in the presence of starches, Lugolʼs solution will change from blue, blue-black, or black, depending on the amount of starch present. Paper bags can be used to test for the presence of lipids. The more lipids present in a substance, the more translucent the bag will become after the substance has been smeared on the bag. Texas College and Career Readiness Initiative 10

11 TCCRI College Readiness Assignments Student Notes Macromolecule Mixes! Introduction Most of the molecules used to build cellular structures are extremely large. For this reason, they are called macromolecules. The four main types of macromolecules carbohydrates, proteins, lipids, and nucleic acids are found in every one of your cells. So, where do these macromolecules and the building blocks to make them come from? Most of them come from the food you eat. You can think of food as mixtures of various macromolecules, including carbohydrates, lipids, and proteins. In this activity, you will perform qualitative chemical tests on standard solutions of carbohydrates (glucose and starch solutions), proteins (gelatin solution), and lipids (vegetable shortening). After recording the results from these standard tests, you will then perform the same qualitative tests on some ordinary foods to detect the presence of carbohydrates (sugars and starches), lipids, and proteins. So, how a qualitative test different from a quantitative test? In a typical qualitative analysis you take a solution of unknown composition and carry out a series of tests to determine the presence or absence of various substances within the solution. The key phrase that makes this a qualitative analysis is presence or absence. In qualitative testing, you are generally looking for yes/no answers. This is in contrast to quantitative testing where you are actually using instruments to measure size, quantity, or other measurable characteristics. In this lab activity, you will perform simple qualitative tests for the presence of biological macromolecules in several food items to establish standards for comparison, identify the macromolecules present in the materials listed, and identify unknown solutions by the macromolecule they contain. You can perform qualitative tests to identify the presence of organic compounds in food using indicators chemical substances that react in a certain way when a particular substance is present. Biuret solution is used to identify the presence of protein. Benedict's solution is used to identify the presence of reducing sugars, such as glucose. Lugol's iodine solution is used to identify the presence of starch. And a brown paper bag can be used to test for lipids. A standard is a positive test for a known substance. Unknown substances can be tested and compared with the standard for positive identification of the substance. Texas College and Career Readiness Initiative S-1 Draft August 2009

12 Detecting Biological Macromolecules Student Notes Directions Getting Started 1. Complete the Introduction to Macromolecules handout for homework. 2. Review safety procedures for working with chemicals. Investigating 1. Put on safety glasses and a lab apron before measuring, pouring, carrying, or touching any chemicals. Safety glasses and an apron must be worn throughout the lab. 2. Label three test tubes: one as protein, one as sugar, and one as starch. You will use these test tubes for your standard tests. Keep your standards until the completion of the lab, as you will want to compare some of your other foods with the standards. 3. Working with your assigned partner, follow the test procedure listed in the Demonstrating the Presence of Carbohydrates, Proteins, and Fats handout. 4. Record all results in the Comparison Data Table on the Data Tables handout. 5. From what you have researched and read about the different types of macromolecules, how would you classify each substance listed on the Comparison Data Table? 6. Before you begin to experiment on the listed materials in the Comparison Data Table, make a prediction. Use a plus sign (+) to indicate predicted presence and a negative sign ( ) to indicate predicted absence. 7. Once you have made your prediction, test each material at the different lab tables and compare your predicted results with the actual experimental result. Was your prediction correct? If not, why not? 8. You will now test two unknown substances. Before testing, predict which biological macromolecules will be found in each unknown. Indicate your predictions in the Unknown Data Table. Use a plus sign (+) to indicate predicted presence, and a negative sign ( ) to indicate predicted absence. 9. Repeat the procedures to test the unknown solutions for all four substances. 10. Identify the qualitative tests you will be using on the top row of the Unknown Data Table. 11. Record your results in the Unknown Data Table; be sure to include color changes. Texas College and Career Readiness Initiative S-2

13 Detecting Biological Macromolecules Student Notes Drawing Conclusions 1. Individually prepare a written report detailing the experimental design and your results. 2. Follow all guidelines given by your instructor for writing the report. Texas College and Career Readiness Initiative S-3

14 Detecting Biological Macromolecules Student Notes Texas College and Career Readiness Initiative S-4

15 TCCRI College Readiness Assignments Student Handouts Introduction to Macromolecules Directions: Use your textbook, reliable web sites, and other resources to complete the chart below. Carbohydrates Main components/structure: Proteins Main components/structure: Main uses in a cell: Main uses in a cell: Lipids Main components/structure: Nucleic Acids Main components/structure: Main uses in a cell: Main uses in a cell: Texas College and Career Readiness Initiative SH-1

16 Detecting Biological Macromolecules Student Handouts Demonstrating the Presence of Carbohydrates, Proteins, and Fats Test for Protein Put about 2 ml of gelatin into the test tube labeled protein. Add 3 drops of Biuret solution. Hold the tube over white paper, and examine any color changes you see. Record the color in the data chart below. Color Chart for Biuret Test No protein Proteins Present shade of blue purple or pink Carbohydrate Test for Glucose and Other Reducing Sugars (these are usually labeled monosaccharides and disaccharides) Put about 3 ml of sugar solution into the test tube labeled sugar. Add 3 drops of Benedictʼs solution. Use the test tube holder to place the test tube in a boiling water bath. Wait 4 or 5 minutes. Use the test tube holder to remove the test tube from the water bath and place it in a test tube rack. Record the color on the data chart on the below. Color Scale for Benedictʼs Test No sugar Highest amount of sugar shade of blue blue-green green green-yellow yellow orange brick red Texas College and Career Readiness Initiative SH-2

17 Detecting Biological Macromolecules Student Handouts Carbohydrate Test for Starch (polysaccharide produced by plants) Place about 3 ml of starch solution into the test tube labeled ʻstarchʼ. Add 3 drops of Lugolʼs solution. Record the color on the data chart below. Color Chart for Lugolʼs Test No starch Highest amount of starch shade of yellowish-brown blue black Test for Lipids (fat) Smear a small amount of vegetable shortening onto a piece of brown paper. Let the smear stand for a few minutes to dry, and then hold the paper up to the light. Record whether or not the spot is translucent on the data chart below. Chart for Lipid Test No starch Highest amount of lipids opaque very translucent Texas College and Career Readiness Initiative SH-3

18 Detecting Biological Macromolecules Student Handouts Data Tables Comparison Data Table Food Distilled Water Egg White Egg Yolk Apple juice Spinach Vegetable oil Potato Whole Milk Honey /Result Result Result Result Result Result Result Result Result Result Proteins Carbohydrate Sugar Carbohydrate Starch Lipids (Fats) Unknown Data Table Unknown # 1 Result Unknown # 2 Result ( ) ( ) ( ) ( ) Texas College and Career Readiness Initiative SH-4