Modern Biology Textbook

Avoid skin Avoid skin contact contact with all with all indicators. indicators. If you do If you do get the Nutrient Lab get the indicator on Biochemistry Unit indicator on your skin your skin wash it wash it Objective  In this lab we will do four simple experiments, using immediatel immediatel indicators, to determine whether common foods contain one or more of y. All y. All these nutrients. indicators indicators will stain Background  will stain clothing. There are four main macromolecules of life: carbohydrates, lipids, clothing. proteins, and nucleic acids. In this lab, we will examine several different substances for the presence of these macromolecules. In order to do this, we will utilize indicators. Please refer to the online lab you already completed to assist you in this activity.

What is an indicator? Several substances, such as benedicts or biurets solution, can indicate the presence, absence, or concentration of another substance. This is shown by a characteristic change when the indicator and the substance being tested come into contact. Changes can be in the form of a color change, temperature change, or presence of bubbles.

The indicators that will be used for this lab are as follows: Benedicts Solution  tests for carbohydrate monomers (monosaccharides) Lugol Iodine Solution  tests for carbohydrate polymers (polysaccharides) Sudan Red Solution  tests for lipids Biuret Solution  tests for proteins

In class, we will test water, starch, corn syrup, oil, and Jello to see what types of organic molecules are in each food. You will perform all 4 tests on each substance. After we have done this part, you will be given several unknowns where you will need to perform all 4 tests again and figure out what each solution is. ------PreLab  THIS SHOULD BE DONE BEFORE YOU COME TO CLASS! DO NOT PRINT THE ENTIRE LAB AND PUT IT IN YOUR LAB NOTEBOOK. ONLY THE DATA TABLES FROM THIS HANDOUT SHOULD BE INCLUDED IN YOUR LAB NOTEBOOK. 1. Title and date of the lab (remember to include your lab partners names and add this lab to your table of contents) 2. Purpose  1-2 sentences describing the overall goal of the experiment; use complete sentences 3. Hypothesis  For your hypothesis, list the 5 solutions we are testing (water, oil, starch, corn syrup, and Jello) and state what macromolecules you believe they will test POSITIVE for. Remember, if you do not guess correctly, that is OK. For example: Starch will test positive for polysaccharides. Do this for each solution. 4. Lab Procedure (see below)  Write a procedure for EACH EXPERIMENT (#1-5). Use your own words to describe the steps in each part of the lab. It should NOT be word for word from this lab sheet – use your own words! You may do a numbered list here. Make sure it is detailed enough that you can complete the lab without this handout. For example – list the # drops of indicator, the # drops of each food, what must be done after that (mix, heat, etc…) and for how long. Also include what you will observe for a positive test. 5. PreLab Questions  See Below; copy each question and ANSWER it BEFORE doing the lab 6. Data  (see below) Copy the data tables into your lab notebook. Give the data tables an appropriate title. ** ANOTHER OPTION FOR THIS LAB IS TO CUT OUT AND TAPE THE DATA TABLES AND THE KEY INTO YOUR LAB NOTEBOOK ** 7. Conclusion questions – I will provide a copy of these for you to use during the lab in class.

------LAB PROCEDURES ***Before beginning any of the test BE SURE TO LABEL YOUR TEST TUBES!!!!

EXPERIMENT #1: BENEDICT’s TEST  monosaccharides Objective: To identify if carbohydrate monomers (monosaccharides) are present in foods. PROCEDURE: a. Place 10 drops of water into test tube #1, 10 drops of starch into test tube #2, 10 drops of corn syrup into test tube #3, 10 drops of oil into test tube #4 and 10 drops of Jello into test tube #5. b. Place 10 drops of benedicts solution into each test tube. c. Thump to mix and place in hot water bath for 2-3 minutes. d. Record your data in your data table – table 1 experiment #1 a. If the solution stayed blue mark your data table with a – (monosaccharides are not present) if it turns green, orange or red mark your data table with a + (monosaccharides are present.) e. Clean-up and return materials.

EXPERIMENT #2: LUGOL’S IODINE TEST  polysaccharides Objective: To identify if carbohydrate polymers (polyasccharides) are present in common foods. PROCEDURE: a. Place 5 drops of water into test tube #1, 5 drops of starch into test tube #2, 5 drops of corn syrup into test tube #3, 5 drops of oil into test tube #4 and 5 drops of Jello into test tube #5. b. Place 3 drops of iodine into each test tube. c. Thump to mix and allow to sit for 2 minutes. d. Record your data in your data table – table 1 experiment #2 a. If the solution stayed yellowish-brown mark your data table with a – (polysaccharides are not present) if it turns bluish-black mark your data table with a + (polysaccharieds are present.) e. Clean-up and return materials.

EXPERIMENT #3: SUDAN RED TEST  lipids Objective: To identify if lipids are present in common foods. PROCEDURE: a. Place 5 drops of water into each test tube. b. Place 5 drops of water into test tube #1, 5 drops of starch into test tube #2, 5 drops of corn syrup into test tube #3, 5 drops of oil into test tube #4 and 5 drops of Jello into test tube #5. c. Place 3 drops of Sudan Red into each test tube. d. Thump to mix and allow to sit for 2 minutes. e. Record your data in your data table – table 1 experiment #3 a. If the solution has concentrated spots of red mark your data table with a + (lipids are present) if it is red throughout (there are not spots) mark your data table with – (lipids are not present). f. Clean-up and return materials.

EXPERIMENT #4: BIURET TEST  proteins Objective: To identify if proteins are present in common foods. PROCEDURE: a. Label 5 test tubes. b. Place 10 drops of water into test tube #1, 10 drops of starch into test tube #2, 10 drops of corn syrup into test tube #3, 10 drops of oil into test tube #4 and 10 drops of Jello into test tube #5. c. Place 10 drops of biurets solution into each test tube. d. Swirl for 30 seconds and let sit for 2 minutes. e. Record your data in your data table – table 1 experiment #4 a. If the solution turns purplish proteins are present (+). f. Clean-up and return materials.

EXPERIMENT #5: FOOD ANALYSIS  identifying the unknowns! Objective: To identify what nutrients are present in common foods. MATERIALS: all of the previous materials & unknown foods PROCEDURE: a. Follow the procedures for experiments #1 - #4 substituting the original solutions (water, starch, corn syrup, oil, and Jello) for the 6 unknowns. b. Record all of the data on data table 2. PreLab Questions

1. What is an indicator? 2. What are the 4 indicators we are going to use and what nutrient does each test for? What color is a positive result for each of the 4 tests? ------Data Tables

Data Table 1: Results from practice nutrient testing Carbohydrate Tests Lipids Test Protein Tests What nutrients does this Experiment Experiment Experiment Experiment Food solution contain? #1 #2 #3 #4 Sample (monosaccharide, Benedict’s Lugol’s Sudan Red Biuret Test polysaccharide, lipid, or protein) Test Iodine Test Test Water Starch Corn Syrup Oil Jello

Date Table 2: Results from unknown nutrient testing

Lipids Protein Are these nutrients What do you think the Carb Tests Test Tests present? unknown food was based

t e e e t t l s d n s s i i d d on the results of the lab p e i i e e e p t r r T i t T T m s a a

o test? a d e s h h e r t S e T c c

n P c i c c R t i d

a a d e d o n s s r o e - - o I a u

n y i o F d l s e l B n u o o B o S P g M u L Unknown A Unknown B Unknown C Unknown D Unknown E Unknown F Conclusion 1. Copy and then Answer the Post Lab Questions (See below  you need to number the question, rewrite the question, and then answer it for full credit) 2. Complete the Analysis Activity (see below)  Instead of copying the data table for this section, you can cut it out and tape it into your lab notebook if you would prefer. 3. You will not have to write a conclusion paragraph for this lab.

Post Lab Questions 1. What was the control in experiments #1-4? 2. Based on your results and our class notes, what are 3 types of foods that should test positive in a benedicts test? 3. Based on your results and our class notes, what a–re 3 types of foods that should test positive in a lugol iodine test? 4. Based on your results and our class notes, what are 3 types of foods that should test positive in a Sudan Red test? 5. Based on your results and our class notes, what are 3 types of foods that should test positive in a Biurets test? 6. Why do proteins react to different indicators than carbohydrates? 7. Why do monosaccharaides react to different indicators than polysaccharides?

Analysis Activity  Analyze the results for the following tests. For each unknown, place a + in the chart if it is a positive test, and a – in the chart if the results suggest a negative test. After marking your + and -, analyze which nutrients are present in each of the unknowns and then come up with a possible food that the unknown could be based on the data.

Analysis Activity Data Table:

Poly- Mono- Unknown saccharides saccharide Proteins Lipids Possible Food

1 2 3 4 5