Purpose:
The purpose for this experiment is to figure out what positive indicator tests for proteins, carbohydrates, and fats. We are also trying to figure out if parts of an egg test positive for protein, carbohydrates, and/or fat.
The purpose for this experiment is to figure out what positive indicator tests for proteins, carbohydrates, and fats. We are also trying to figure out if parts of an egg test positive for protein, carbohydrates, and/or fat.
Materials:
eggs beaker, 250 ml white vinegar plastic wrap slotted spoon sodium chloride distilled water beaker, 100 ml pipets, 5 ml pipet pump, green |
tubes, glasss, 13x100 mm peg racks for 13x100 mm tubes glucose (dextrose) benedict's solution Hot plate stirrer Test tube holder Starch, solution Lugol's Iodine Solution Voertex mixer |
Gelatin Sodium hydroxide Cupric Sulfate 5-hydrate Oil Sudan IV Solution Scalpal handles, #4 Scalpal blades, #22, for #4 handles Trays, plastic |
Procedure:
Part I
1. Put one uncooked egg into a beaker of white vinegar, then label and cover it with plastic wrap. Next leave it alone for 24 - 48 hours and skip to part two while waiting for the egg shell to dissolve.
2. After the shell has dissolved, carefully pick up the egg with the slotted spoon and rinse it with water to remove the vinegar. What chemicals were involved as reactants?
3. Feel the outer membrane because it is a good model of a cell membrane. They are thin, flexible, and permeable to some substances. To see if water can enter/exit, place the egg in a beaker of 5% NaCl solution for 24 hours and describe the appearance after. What caused the change?
4. Rinse off the egg and place it in a beaker of distilled water for 24 hours. Describe its appearance and how it changed.
5. Slice open the eggs membrane without cutting the yoke and drain the egg white into the 100 ml beaker.
6. place the yoke in a new beaker and set aside the egg membrane.
Part II
Test four solutions and record the data in the table.
Monosaccharide Indicator Standard Test:
1. Test for glucose: mix 2 ml of of 2% glucose solution with 2 ml of Benedict's solution. Boil with water (100 ml water in a 250 ml beaker) for two minutes and record the changes of color over time.
2. Test for water: mix 2 ml of deionized water with 2 ml of Benedict's solution. Boil with water (100 ml water in a 250 ml beaker) for two minutes and record the changes of color over time.
Starch Indicator Standard Test:
1. Test for starch: mix 2 ml of mixed starch suspension and 0.25 ml of Lugol's iodine. Swirl to mix and record color changes.
2. Test for water: mix 2 ml of deionized water and 0.25 ml of Lugol's iodine. Swirls to mix and record color changes.
Protein indicator Standard Test:
Warning: NaOH should be handled with caution and lab protection.
1. Test for protein: gently mix 2 ml of gelatin and 1 ml of biuret solution in circles. Then record color changes after 30 seconds.
2. Test for water: gently mix 2 ml of deionized water and 1 ml of biuret solution in circles. Then record the color changes after 30 seconds.
Lipid Indicator Standard Test:
1. Test for lipids: mix 2 ml of oil and 60 ,ul of sudan IV. Then record the color changes after 30 sec.
2. Test for water: mix 2 ml of deionized water and 60 ,ul of sudan IV. Then record the color changes after 30 sec.
Part III:
Test the egg components for monosaccharides, starch, protein, and lipid.
1. Do the same experiments as in part II, except replace the sugar, starch, protein, and fat with the egg components. Don't add the standard solutions.
2. Record the results of the egg membrane, the yolk, and egg white for all four molecules on the graph.
3. Give numerical values to each result (3 = very strong, 2 = strong, 1 = weak, and 0 = no change) and a brief description of color changes.
Part I
1. Put one uncooked egg into a beaker of white vinegar, then label and cover it with plastic wrap. Next leave it alone for 24 - 48 hours and skip to part two while waiting for the egg shell to dissolve.
2. After the shell has dissolved, carefully pick up the egg with the slotted spoon and rinse it with water to remove the vinegar. What chemicals were involved as reactants?
3. Feel the outer membrane because it is a good model of a cell membrane. They are thin, flexible, and permeable to some substances. To see if water can enter/exit, place the egg in a beaker of 5% NaCl solution for 24 hours and describe the appearance after. What caused the change?
4. Rinse off the egg and place it in a beaker of distilled water for 24 hours. Describe its appearance and how it changed.
5. Slice open the eggs membrane without cutting the yoke and drain the egg white into the 100 ml beaker.
6. place the yoke in a new beaker and set aside the egg membrane.
Part II
Test four solutions and record the data in the table.
Monosaccharide Indicator Standard Test:
1. Test for glucose: mix 2 ml of of 2% glucose solution with 2 ml of Benedict's solution. Boil with water (100 ml water in a 250 ml beaker) for two minutes and record the changes of color over time.
2. Test for water: mix 2 ml of deionized water with 2 ml of Benedict's solution. Boil with water (100 ml water in a 250 ml beaker) for two minutes and record the changes of color over time.
Starch Indicator Standard Test:
1. Test for starch: mix 2 ml of mixed starch suspension and 0.25 ml of Lugol's iodine. Swirl to mix and record color changes.
2. Test for water: mix 2 ml of deionized water and 0.25 ml of Lugol's iodine. Swirls to mix and record color changes.
Protein indicator Standard Test:
Warning: NaOH should be handled with caution and lab protection.
1. Test for protein: gently mix 2 ml of gelatin and 1 ml of biuret solution in circles. Then record color changes after 30 seconds.
2. Test for water: gently mix 2 ml of deionized water and 1 ml of biuret solution in circles. Then record the color changes after 30 seconds.
Lipid Indicator Standard Test:
1. Test for lipids: mix 2 ml of oil and 60 ,ul of sudan IV. Then record the color changes after 30 sec.
2. Test for water: mix 2 ml of deionized water and 60 ,ul of sudan IV. Then record the color changes after 30 sec.
Part III:
Test the egg components for monosaccharides, starch, protein, and lipid.
1. Do the same experiments as in part II, except replace the sugar, starch, protein, and fat with the egg components. Don't add the standard solutions.
2. Record the results of the egg membrane, the yolk, and egg white for all four molecules on the graph.
3. Give numerical values to each result (3 = very strong, 2 = strong, 1 = weak, and 0 = no change) and a brief description of color changes.
Data/Results
Part I:
Day 1 - we placed the eggs in a beaker of vinegar for 48 hours.
Day 2 - The eggs shell was completely dissolved so we then drained the vinegar, rinsed the egg, and placed it in salt water for 24 hours. In this part of the experiment the egg absorbed the salt and released some water.
Day 3 - Since the egg lost some water we observed that it was smaller. We then drained the salt water, rinsed the egg, and placed it in a beaker of water. Later in part III when we cut the egg open it popped from the pressure of regaining its water.
Part II:
Our test results are in the table below.
Day 1 - we placed the eggs in a beaker of vinegar for 48 hours.
Day 2 - The eggs shell was completely dissolved so we then drained the vinegar, rinsed the egg, and placed it in salt water for 24 hours. In this part of the experiment the egg absorbed the salt and released some water.
Day 3 - Since the egg lost some water we observed that it was smaller. We then drained the salt water, rinsed the egg, and placed it in a beaker of water. Later in part III when we cut the egg open it popped from the pressure of regaining its water.
Part II:
Our test results are in the table below.
Part III:
Each of the three components are measured in the table to represent if the substance is positive or negative. (3 = very strong (positive), 2 = strong, 1 = weak, 0 = no change (negative)).
Each of the three components are measured in the table to represent if the substance is positive or negative. (3 = very strong (positive), 2 = strong, 1 = weak, 0 = no change (negative)).
Data Analysis/Conclusion
Through out this project we were able to answer the questions in the purpose. For the first question we found that the positive indicator color for proteins is a purple/blue, for carbohydrates the color is a black/brown, and the color for fats is milky pink color. After finding the positive and negative indicator colors, we used the information to test parts of the egg. We found that the yolk tests positive for protein and fat. The membrane tests positive for glucose, carbohydrates, and fat. The egg white tests positive for glucose, carbohydrates, and protein.
After doing this lab, we realized that there might have been a few things that could have changed our results making experimental errors. The main thing we did that may have led to false results is that our pipets weren’t labeled well so we could have cross-contaminated some of the materials. Next time if we were to do this experiment again, we would label all our pipets first so there would be no confusion of which one to use and less chances off cross-contamination. Next time we would also do multiple tests at a time to save time earlier on since we only did that for the last two tests. Knowing how to read indicators is very important because they can be used to measure the clarity of water, what a substance may contain, and can even help in determining whether or not someone has diabetes.
After doing this lab, we realized that there might have been a few things that could have changed our results making experimental errors. The main thing we did that may have led to false results is that our pipets weren’t labeled well so we could have cross-contaminated some of the materials. Next time if we were to do this experiment again, we would label all our pipets first so there would be no confusion of which one to use and less chances off cross-contamination. Next time we would also do multiple tests at a time to save time earlier on since we only did that for the last two tests. Knowing how to read indicators is very important because they can be used to measure the clarity of water, what a substance may contain, and can even help in determining whether or not someone has diabetes.
Reflection
Overall I liked this lab because my partner and I worked together well and finished the project on time. I found it very interesting how the egg would shrink and expand in the different solutions since it was either gaining or losing water. To me I believe my partner and I collaborated together very well. We both took leadership at part, we listened to each other well, we didn’t argue, and we both kept on track. Next time if we were to do this experiment again, we would label our pipets better and make sure things are thoroughly cleaned or replaced with a new clean material. This may have led to some experimental error in some of our experiments because it was difficult to determine which pipet was which and some of the test tubes that we could reuse may not have been cleaned enough either. In the end I think this lab went very well and we completed it right and on time.