Dissecting A Cell And Examining Its Components
PURPOSE:
What are positive indicator tests for proteins, carbohydrates, and fats? Do parts of an egg test positive for proteins, carbohydrate, and/or fats?
What are positive indicator tests for proteins, carbohydrates, and fats? Do parts of an egg test positive for proteins, carbohydrate, and/or fats?
MATERIALS:
Eggs Beaker 250mL White Vinegar Plastic Wrap Slotted Spoon Sodium Chloride Distilled Water Beaker 100mL Pipets 5mL Pipet Pump, green Tubes, glass, 13x100 mm Peg racks for 13x100 mm tubes Glucose (dextrose) |
Benedict's Solution Hot Plate Stirrer Test Tube Holder Starch,soluble Lugols 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 1
1. Place raw egg in white vinegar. Label and cover for 24 to 48 hours.
2. After the shell is dissolved, carefully lift out of beaker and rinse with water.
3.Feel the egg. Place egg in 5% NaCl solution for 24 hours.
4. Rinse egg. Place egg in distilled water for 24 hours.
5. Gently slice open egg. Let the white drip through through slots into beaker. Don't pierce the yolk.
6. Place egg yolk in another beaker and set aside membranes.
1. Place raw egg in white vinegar. Label and cover for 24 to 48 hours.
2. After the shell is dissolved, carefully lift out of beaker and rinse with water.
3.Feel the egg. Place egg in 5% NaCl solution for 24 hours.
4. Rinse egg. Place egg in distilled water for 24 hours.
5. Gently slice open egg. Let the white drip through through slots into beaker. Don't pierce the yolk.
6. Place egg yolk in another beaker and set aside membranes.
Procedure: (Part 2 - Testing Standard Solutions)
Monosaccharide Indicator Standard Test:
1. Test for glucose: 2 mL of a 2% glucose solution + 2 mL of Benedict's solution. Heat for 2 minutes in 100 mL of water in a 250-mL beaker at 100 degrees Celsius. Record all color changes.
2. Test for water (negative control): 2 mL of deionized water + 2 mL of Benedict's solution. Heat for 2 minutes in a boiling hot water bath (dimensions above) and record all color changes.
Monosaccharide Indicator Standard Test:
1. Test for glucose: 2 mL of a 2% glucose solution + 2 mL of Benedict's solution. Heat for 2 minutes in 100 mL of water in a 250-mL beaker at 100 degrees Celsius. Record all color changes.
2. Test for water (negative control): 2 mL of deionized water + 2 mL of Benedict's solution. Heat for 2 minutes in a boiling hot water bath (dimensions above) and record all color changes.
Starch Indicator Standard Test
1. Test for Starch: mix 2 mL of mixed starch suspension with 0.25 mL of Lugol's solution. Record all color changes and how long it takes for appearance of color.
2. Test for water: mix 2 mL of deionized water with 0.25 mL of Lugol's iodine. Gently swirl to mix and DO NOT HEAT. Record the color change.
1. Test for Starch: mix 2 mL of mixed starch suspension with 0.25 mL of Lugol's solution. Record all color changes and how long it takes for appearance of color.
2. Test for water: mix 2 mL of deionized water with 0.25 mL of Lugol's iodine. Gently swirl to mix and DO NOT HEAT. Record the color change.
Protein Indicator Standard Test:
1. Test for protein: 2 mL of gelatin solution + 0.5 mL of 10% NaOH + 0.25 mL of 5% copper sulfate and gently mix. Mix well. Record color change after 30 seconds.
2. Test for water (negative control): 2 mL of deionized water in a test tube + 0.5 mL of 10% NaOh + 0.25 mL of 5% CuSO4, and gently mix well. Record color change after 30 seconds
1. Test for protein: 2 mL of gelatin solution + 0.5 mL of 10% NaOH + 0.25 mL of 5% copper sulfate and gently mix. Mix well. Record color change after 30 seconds.
2. Test for water (negative control): 2 mL of deionized water in a test tube + 0.5 mL of 10% NaOh + 0.25 mL of 5% CuSO4, and gently mix well. Record color change after 30 seconds
Lipid Indicator Standard Test
1.Test for Lipids: Place a drop of oil on piece of brown paper bag. Let it dry for 10 min. Hold paper to light. Record how much light passes through the spot.
2. Test for water: place drop of water on piece of brown paper bag. Let it dry for 10 min. Hold paper to light. Record how much light passes through the spot.
1.Test for Lipids: Place a drop of oil on piece of brown paper bag. Let it dry for 10 min. Hold paper to light. Record how much light passes through the spot.
2. Test for water: place drop of water on piece of brown paper bag. Let it dry for 10 min. Hold paper to light. Record how much light passes through the spot.
Procedure: (Part 3 - Molecular Composition of Egg Components)
1. Conduct each indicator test (Part II) but substitute each egg component to be tested for sugar, starch, protein, or fat.
2. Record results of testing the egg membranes: the yolk (cell cytoplasm) and egg white.
3. Give a numerical value to each test result using the following scale: [ 3 = very strong/positive test, 2 = strong/positive test, 1 = weak/positive test, 0 = no color change in indicator/negative ]
1. Conduct each indicator test (Part II) but substitute each egg component to be tested for sugar, starch, protein, or fat.
2. Record results of testing the egg membranes: the yolk (cell cytoplasm) and egg white.
3. Give a numerical value to each test result using the following scale: [ 3 = very strong/positive test, 2 = strong/positive test, 1 = weak/positive test, 0 = no color change in indicator/negative ]
Results
Part 1
1. Egg in Vinegar : The hard outside of the shell dissolved into the vinegar, leaving just the thin membrane of the egg.
2. Egg + Salt Water : According to the scientific laws, areas of higher pressure diffuse to areas of lower pressure. In the experiment, this occurred during this particular procedure. The salt water passed through the membrane into the egg, while the regular water inside left the egg. Because of this diffusion, the egg appeared smaller.
3. Egg + Water: When the egg is doused back in water, the saltwater solution inside the egg returns to outside the egg. The regular water in the beaker enters the egg, causing it to be bigger and bloated. This explains why when we cut a slit into the membrane, the egg contents seemed to burst outward.
2. Egg + Salt Water : According to the scientific laws, areas of higher pressure diffuse to areas of lower pressure. In the experiment, this occurred during this particular procedure. The salt water passed through the membrane into the egg, while the regular water inside left the egg. Because of this diffusion, the egg appeared smaller.
3. Egg + Water: When the egg is doused back in water, the saltwater solution inside the egg returns to outside the egg. The regular water in the beaker enters the egg, causing it to be bigger and bloated. This explains why when we cut a slit into the membrane, the egg contents seemed to burst outward.
Part 2
STANDARD (MOLECULE TESTED)
Glucose Starch Protein Fat |
INDICATOR USED
Benedict's solution Lugol's iodine Biuret reagents Sudan 4 |
POSITIVE CONTROL TEST
-At around 1:30, the solution turned a variety of colors ranging from green, brown, and even its original blue. -The solution had turned a dark, reddish brown. -The solution seemed to have turn a pretty, deep purple color. - The liquid turned to a variety of pinks and reds. |
NEGATIVE CONTROL TEST
-There was no color change. -The solution orange. - The solution turned a light white, almost clear color. - The liquid turned into a very light, clear,pink. |
Part 3: Testing egg components
Egg component tested
Egg Membrane Yolk Egg White |
Benedicts solution
3 2 2 |
Iodine
1 2 2 |
Biuret Reagent
3 1 2 |
Sudan IV
1 0 2 |
CONCLUSION The Benedicts solution changed from blue to murky green, then a rusty orange color. The iodine turned from orange-brown to dark brown almost black color. The Biuret was the prettiest to me since it had turned from a clear color to a deep purple. The sudan was also pretty. It turned from a clear to a light, light, pink.
This whole lab was based on the chemical reactions of parts of the egg. But not all the test were extremely reactive. For example, the yolk of egg tested average in iodine and bendicts solution. But, for the IV test and the Biuret test, the results were none. Another example is the egg membrane, the egg membrane tested under average for the sudan and Iodine, and above average for bendict solution and biuret. The egg whites tested average to a little above average for all the tests.
Many errors that could have occurred during the test, but the most common ,mistakes possible were the test tubes not being cleaned properly. We used the test tubes with different chemicals for several different test. The only actual error I know we did was when we mixed the yolk with the distilled water. It was a yolk mixed solution that we tested and we never really got an actual piece of the yolk into the test tube which have caused the error in results.
This whole lab was based on the chemical reactions of parts of the egg. But not all the test were extremely reactive. For example, the yolk of egg tested average in iodine and bendicts solution. But, for the IV test and the Biuret test, the results were none. Another example is the egg membrane, the egg membrane tested under average for the sudan and Iodine, and above average for bendict solution and biuret. The egg whites tested average to a little above average for all the tests.
Many errors that could have occurred during the test, but the most common ,mistakes possible were the test tubes not being cleaned properly. We used the test tubes with different chemicals for several different test. The only actual error I know we did was when we mixed the yolk with the distilled water. It was a yolk mixed solution that we tested and we never really got an actual piece of the yolk into the test tube which have caused the error in results.
REFLECTION I found seeing how the egg reacted to different chemicals and how chemicals reacted to each other interesting. I believe that my partner and I worked and collaborated well during the lab. We worked at a good pace and produced the results we needed. We communicated with each other well. The only thing Iwe could have done differently is we could have handled the egg more carefully. The only problem we had was when we were supposed to make a small incision and the egg exploded everywhere. So, we could've been more careful cutting the egg and be more detailed with our results.