Lab 2A ~ Dissecting a Cell and Examining its Components
Purpose
The purpose of this lab is to find out what are positive indicators for protein, carbohydrates, and fats. We also need to discover whether the parts of an egg test positive for protein, carbohydrates, and fats.
The purpose of this lab is to find out what are positive indicators for protein, carbohydrates, and fats. We also need to discover whether the parts of an egg test positive for protein, carbohydrates, and fats.
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, glass, 13x100 mm Peg Racks for 13x100mm tubes Glucose (dextrose) Benedict's Solution Hot plate Stirrer Test Tube Holder Starch, Soluble Logul's Iodine Solution Vortex Mixer Gelatin |
Sodium Hydroxide Cupric Sulfate 5-Hydrate Oil Sudan IV Solution Scalpel Handles, #4 Scalpel Blades, #22, for #4 Handles Trays, Plastic |
Procedure
Part I: Separating Cell Structures
1. Place an uncooked egg into a beaker of white vinegar. Label and cover it with plastic wrap. Leave it for 24 to 48 hours. While the shell dissolves, proceed to Part II.
2. After 24 to 48 hours, the shell should have dissolved in the vinegar (acetic acid). Gently pick up the egg with a slotted spoon and rinse it in water to remove the vinegar. A chemical reaction has happened here. What chemicals were involved as reactants and products?
3. Feel the outer membranes of the cell. The outer membrane, which is different from the membrane around the yolk, provides a good model of a cell membrane. They are thin and flexible. They are permeable to some substances. To verify that water can enter and leave the cell easily, place the egg in a beaker of 5% NaCl solution for 24 hours. Describe the appearance of the egg after 24 hours. What may have caused the change in appearance?
4. Gently rinse off the egg again with water. Then place the egg in a beaker of distilled water for 24 hours. Describe the appearance of the egg after 24 hours. What caused the change in appearance?
5. To retrieve the egg cell, gently slice open the egg's membranes, and let the egg white drip through the slots of the spoon into a 100 mL beaker. Try to get all of the egg white into the beaker without piercing the yolk (egg cell with a clear, flimsy cell membrane around it).
6. Place the egg yolk into another beaker, and set aside the egg membranes.
Part II: Testing Standard Solutions
Monosaccharide Indicator Standard Test
1. This is a test for glucose. Mix 2 mL of a 2% glucose solution with 2 mL of Benedict's solution in a test tube. Heat them for 2 minutes in a boiling hot water bath and record all color changes and the length of time for each color to appear.
2. This is a test for water. Mix 2 mL of deionized water with 2 mL of Benedict's solution in a test tube. Heat for 2 minutes in a boiling hot water bath and record all changes in color and the length of time for each color to appear.
Starch Indicator Standard Test
1. This is a test for starch. Mix 2 mL of well-mixed starch suspension with 0.25 mL of Lugol's Iodine in a test tube. Gently mix and record the color change.
2. This is a test for water. Mix 2 mL of deionized water with 0.25 mL of Lugol's Iodine. Gently mix and record the color change.
Protein Indicator Standard Test
1. This is a test for protein. Put 2 mL of gelatin in a test tube and add 1 mL of Biuret and vortex the mix. Add 0.25 mL of 5% copper solfate and mix. Mix well and record the color change after 30 seconds.
2. This is a test for water. Put 2 mL of deionized water in a test tube and add 1 mL of Biuret and gently vortex to mix. Add 0.25 mL of 5% Copper Sulfate and mix well. Record color change after 30 seconds.
Lipid Indicator Standard Test
1. This is a test for lipids. Put a drop of oil on a piece of brown bag and let it dry for 10 minutes. Then hold the paper up to light and record how translucient the bag is.
2. This is a test for water. Place a drop of water on a piece of brown paper bag and let it dry for 10 minutes. Hold it up to the light and record how translucsent the bag is.
Part III: Molecular Composition of Egg Components
1. Do all of the indicator test in Part II, but this time substitute the egg so it will be tested. Everything is the same, only the egg variable is being changed. Do not add any of the standard solutions.
2. Record the results of testing the egg membranes, yolk, and egg white for all four molecules.
3. Give a numeric value to each test result using this key. Then include a brief description of the color changes.
3 = very strong / positive test
2 = strong / positive test
1 = weak / positive test
0 = no color change in indicator / negative test
Part I: Separating Cell Structures
1. Place an uncooked egg into a beaker of white vinegar. Label and cover it with plastic wrap. Leave it for 24 to 48 hours. While the shell dissolves, proceed to Part II.
2. After 24 to 48 hours, the shell should have dissolved in the vinegar (acetic acid). Gently pick up the egg with a slotted spoon and rinse it in water to remove the vinegar. A chemical reaction has happened here. What chemicals were involved as reactants and products?
3. Feel the outer membranes of the cell. The outer membrane, which is different from the membrane around the yolk, provides a good model of a cell membrane. They are thin and flexible. They are permeable to some substances. To verify that water can enter and leave the cell easily, place the egg in a beaker of 5% NaCl solution for 24 hours. Describe the appearance of the egg after 24 hours. What may have caused the change in appearance?
4. Gently rinse off the egg again with water. Then place the egg in a beaker of distilled water for 24 hours. Describe the appearance of the egg after 24 hours. What caused the change in appearance?
5. To retrieve the egg cell, gently slice open the egg's membranes, and let the egg white drip through the slots of the spoon into a 100 mL beaker. Try to get all of the egg white into the beaker without piercing the yolk (egg cell with a clear, flimsy cell membrane around it).
6. Place the egg yolk into another beaker, and set aside the egg membranes.
Part II: Testing Standard Solutions
Monosaccharide Indicator Standard Test
1. This is a test for glucose. Mix 2 mL of a 2% glucose solution with 2 mL of Benedict's solution in a test tube. Heat them for 2 minutes in a boiling hot water bath and record all color changes and the length of time for each color to appear.
2. This is a test for water. Mix 2 mL of deionized water with 2 mL of Benedict's solution in a test tube. Heat for 2 minutes in a boiling hot water bath and record all changes in color and the length of time for each color to appear.
Starch Indicator Standard Test
1. This is a test for starch. Mix 2 mL of well-mixed starch suspension with 0.25 mL of Lugol's Iodine in a test tube. Gently mix and record the color change.
2. This is a test for water. Mix 2 mL of deionized water with 0.25 mL of Lugol's Iodine. Gently mix and record the color change.
Protein Indicator Standard Test
1. This is a test for protein. Put 2 mL of gelatin in a test tube and add 1 mL of Biuret and vortex the mix. Add 0.25 mL of 5% copper solfate and mix. Mix well and record the color change after 30 seconds.
2. This is a test for water. Put 2 mL of deionized water in a test tube and add 1 mL of Biuret and gently vortex to mix. Add 0.25 mL of 5% Copper Sulfate and mix well. Record color change after 30 seconds.
Lipid Indicator Standard Test
1. This is a test for lipids. Put a drop of oil on a piece of brown bag and let it dry for 10 minutes. Then hold the paper up to light and record how translucient the bag is.
2. This is a test for water. Place a drop of water on a piece of brown paper bag and let it dry for 10 minutes. Hold it up to the light and record how translucsent the bag is.
Part III: Molecular Composition of Egg Components
1. Do all of the indicator test in Part II, but this time substitute the egg so it will be tested. Everything is the same, only the egg variable is being changed. Do not add any of the standard solutions.
2. Record the results of testing the egg membranes, yolk, and egg white for all four molecules.
3. Give a numeric value to each test result using this key. Then include a brief description of the color changes.
3 = very strong / positive test
2 = strong / positive test
1 = weak / positive test
0 = no color change in indicator / negative test
Data Results
Part I: Separating Cell Structures
Day 1: Put the egg in vinegar for 24 hours.
Day 2: The chemical reaction the occurred between CaCO3 + CH3COOH created H2CO3 + H2O + CO2. The shell was dissolved. We then put it in salt water.
Day 3: The egg was smaller because of the salt water. The salt drew the water out of the egg. Then put the egg in deionized water.
Day 4: Adding water to the egg made the egg bigger. We then cut the egg open and it burst apart like a water balloon. This is also evidence to show that more water had entered the egg.
Part II: Testing Standard Solutions
The second part of this lab was to document what happened to known items that had or did not have protein, carbohydrates, fats, or glucose. You also had to record any color changes.
Day 1: Put the egg in vinegar for 24 hours.
Day 2: The chemical reaction the occurred between CaCO3 + CH3COOH created H2CO3 + H2O + CO2. The shell was dissolved. We then put it in salt water.
Day 3: The egg was smaller because of the salt water. The salt drew the water out of the egg. Then put the egg in deionized water.
Day 4: Adding water to the egg made the egg bigger. We then cut the egg open and it burst apart like a water balloon. This is also evidence to show that more water had entered the egg.
Part II: Testing Standard Solutions
The second part of this lab was to document what happened to known items that had or did not have protein, carbohydrates, fats, or glucose. You also had to record any color changes.
Part III: Molecular Composition of Egg Components
Below is a table containing data on whether the egg yolk, membrane, or white tested positive for glucose,carbohydrates, water, or fats. It also includes all color changes to the egg during testing.
Below is a table containing data on whether the egg yolk, membrane, or white tested positive for glucose,carbohydrates, water, or fats. It also includes all color changes to the egg during testing.
Data Analysis
Purpose Question - What are positive indicator tests for proteins, carbohydrates, and fats? Do parts of an egg test positive for protein, carbohydrates, and fats?
Monosarrharide Test - the positive indicator for this test was to have a orangish-brown liquid at the end of two minutes.
Starch Test - the liquid stayed black.
Protein Test - after 30 seconds, the mixture turns black.
Lipid Test - it turns into a pinkish, thick substance.
The egg white tested positive for glucose, starch, protein, and fat. The egg yolk tested positive for glucose, protein, and fat. It tested negative for starch. The egg membrane tested positive for glucose but tested negative for starch, protein, and fat.
Identify errors that may have lead to false test results. Suggest variations.
Human error is the number one thing that may have led to false test results. Human errors like improper measurement could have led to to false results.
Propose another application for indicator test.
Another indicator test is a PED (Performance Enhancing Drug) test. This test occurs most around professional athletes. If an athlete takes a test and tests positive for PED's, they are suspended. To take the test, you pee in a cup and doctors test for the invasive drug.
Monosarrharide Test - the positive indicator for this test was to have a orangish-brown liquid at the end of two minutes.
Starch Test - the liquid stayed black.
Protein Test - after 30 seconds, the mixture turns black.
Lipid Test - it turns into a pinkish, thick substance.
The egg white tested positive for glucose, starch, protein, and fat. The egg yolk tested positive for glucose, protein, and fat. It tested negative for starch. The egg membrane tested positive for glucose but tested negative for starch, protein, and fat.
Identify errors that may have lead to false test results. Suggest variations.
Human error is the number one thing that may have led to false test results. Human errors like improper measurement could have led to to false results.
Propose another application for indicator test.
Another indicator test is a PED (Performance Enhancing Drug) test. This test occurs most around professional athletes. If an athlete takes a test and tests positive for PED's, they are suspended. To take the test, you pee in a cup and doctors test for the invasive drug.
Reflection
1. What did you like/find interesting?
I liked seeing the egg without a shell. It was neat to see and it was cool because you normally never see an egg like this. I also liked cutting open the egg beause it exploded like a water balloon.
2. How did you and your partner collaborate?
My lab partner was Jason Franks. We worked together well and completed the lab in a timely manner. We communicated well and were able to express what we needed to do to get the project moving. We helped each other with our work and listened to each other's thought's on what happened to the egg. Overall, we worked well together because we communicated well, used our time well, and collaborated well.
3. What would you do differently next time?
Next time, I would be more organized. The table that we worked at was very messy and that led to tougher cleanup. We used too many pipets because we didn't label them well. Things were thrown about on the table and you had to be careful not to spill on your notebook or somebody else's. There were dirty vials and other things that led to more time being wasted cleaning them than doing the experiment. If we could do something different;y the next time, I would vote for more organization among the groups.
I liked seeing the egg without a shell. It was neat to see and it was cool because you normally never see an egg like this. I also liked cutting open the egg beause it exploded like a water balloon.
2. How did you and your partner collaborate?
My lab partner was Jason Franks. We worked together well and completed the lab in a timely manner. We communicated well and were able to express what we needed to do to get the project moving. We helped each other with our work and listened to each other's thought's on what happened to the egg. Overall, we worked well together because we communicated well, used our time well, and collaborated well.
3. What would you do differently next time?
Next time, I would be more organized. The table that we worked at was very messy and that led to tougher cleanup. We used too many pipets because we didn't label them well. Things were thrown about on the table and you had to be careful not to spill on your notebook or somebody else's. There were dirty vials and other things that led to more time being wasted cleaning them than doing the experiment. If we could do something different;y the next time, I would vote for more organization among the groups.