lab 2a dissecting an egg cell
Purpose: What are the positive indicator tests for proteins, carbs, and fats? Do parts of an egg test positive for protein, carbs, and/or fats?
Materials:
Eggs Tubes, glass, 13x100 mm Gelatin
Beaker, 250 ml Peg racks for 13x100 mm tubes Sodium hydroxide
White vinegar Glucose (dextrose) Cupric sulfate 5-hydrate
Plastic wrap Benedict's solution Oil
Slotted spoon Hot plate stirrer Sudan IV solution
Sodium chloride Test tube holder Scalpel handles, #4
Distilled water Starch, soluble Scalpel blades, #22, for #4
Beaker, 100 ml Lugol's Iodine solution Trays, plastic
Pipets, 5 ml Vortex mixer
pipet pump, green
Procedure:
Part 1: Separating Cell Structures
1. Place an uncooked egg into a beaker of white vinegar. Label and cover it with plastic wrap. Leave it out for about 24-48 hours.
2. After 24-48 hours, the egg shell should have dissolved in the vinegar. Gently pick up the egg with a slotted spoon and rinse it in water to remove the vinegar fluid. A chemical reaction has occurred.
3. Feel the outer membranes of the cell
4. Place the egg in a beaker of 5% NaCl solution for 24 hours. Describe the appearance of egg.
5. Rinse again. Then place the egg in a beaker of distilled water for 24 hours. Describe the appearance of egg.
6. Slice open the egg's membranes to get to the egg cell, and let the egg white drip through the slots of the spoon into a 100-mL beaker.
7. Place the egg yolk (egg cell with a clear, flimsy cell membrane around it) into another beaker, and set aside the egg membranes.
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.
Starch Indicator Standard Test:
1. Test for Starch: 2 mL of well-mixed starch suspension with 0.25 mL of Lugol's iodine. Mix. Don't heat. Record color change.
2. Test for water (negative control): In a test tube, mix 2 mL of deionized water with 0.25 mL of Lugol's iodine. Mix. Don't heat. Record 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.
Lipid Indicator Standard Test:
1. Test for Lipids: Place a drop of oil (100% fat) on a piece of brown paper bag. Let it dry for 10 minutes. Hole paper to light, record how much passes through the spot.
2. Test for water: Place drop of water on a piece of brown paper bag. Let it dry for 10 minutes. Hold paper to light, record amount of passing light.
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
Materials:
Eggs Tubes, glass, 13x100 mm Gelatin
Beaker, 250 ml Peg racks for 13x100 mm tubes Sodium hydroxide
White vinegar Glucose (dextrose) Cupric sulfate 5-hydrate
Plastic wrap Benedict's solution Oil
Slotted spoon Hot plate stirrer Sudan IV solution
Sodium chloride Test tube holder Scalpel handles, #4
Distilled water Starch, soluble Scalpel blades, #22, for #4
Beaker, 100 ml Lugol's Iodine solution Trays, plastic
Pipets, 5 ml Vortex mixer
pipet pump, green
Procedure:
Part 1: Separating Cell Structures
1. Place an uncooked egg into a beaker of white vinegar. Label and cover it with plastic wrap. Leave it out for about 24-48 hours.
2. After 24-48 hours, the egg shell should have dissolved in the vinegar. Gently pick up the egg with a slotted spoon and rinse it in water to remove the vinegar fluid. A chemical reaction has occurred.
3. Feel the outer membranes of the cell
4. Place the egg in a beaker of 5% NaCl solution for 24 hours. Describe the appearance of egg.
5. Rinse again. Then place the egg in a beaker of distilled water for 24 hours. Describe the appearance of egg.
6. Slice open the egg's membranes to get to the egg cell, and let the egg white drip through the slots of the spoon into a 100-mL beaker.
7. Place the egg yolk (egg cell with a clear, flimsy cell membrane around it) into another beaker, and set aside the egg membranes.
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.
Starch Indicator Standard Test:
1. Test for Starch: 2 mL of well-mixed starch suspension with 0.25 mL of Lugol's iodine. Mix. Don't heat. Record color change.
2. Test for water (negative control): In a test tube, mix 2 mL of deionized water with 0.25 mL of Lugol's iodine. Mix. Don't heat. Record 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.
Lipid Indicator Standard Test:
1. Test for Lipids: Place a drop of oil (100% fat) on a piece of brown paper bag. Let it dry for 10 minutes. Hole paper to light, record how much passes through the spot.
2. Test for water: Place drop of water on a piece of brown paper bag. Let it dry for 10 minutes. Hold paper to light, record amount of passing light.
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
Data/results:
Part I.
1. We placed an uncooked egg into a jar of vinegar for about 48 hours.
2. Shell was mostly dissolved, we cleaned the jar and egg and then placed the egg into a salt water solution for another 24 hours.
3. After the 24 hours, we cleaned the egg and jar and put the egg into regular tap water over the weekend for a period of time for about 4 days.
Part II and Part III data table:
Part I.
1. We placed an uncooked egg into a jar of vinegar for about 48 hours.
2. Shell was mostly dissolved, we cleaned the jar and egg and then placed the egg into a salt water solution for another 24 hours.
3. After the 24 hours, we cleaned the egg and jar and put the egg into regular tap water over the weekend for a period of time for about 4 days.
Part II and Part III data table:
Part 2/3 Data table | |
File Size: | 27 kb |
File Type: |
Conclusion: Positive indicator tests for fats, proteins, and carbohydrates can be done by using chemical solutions to test substances depending on their color change. We tested the negative and positive controls for fats, glucose, proteins, and carbohydrates. We then took the results and substituted them for parts of an egg: the egg membrane, egg yolk (egg cell), and egg whites. We conducted experiments to test these different parts of the egg and recorded them to a table (data table above). With this data, we were able to calculate whether the substances were positive or negative.
-The egg whites tested positive for all tests but tested weakly for glucose and strong for protein and starch.
-The egg membrane tested positive for all tests, weak for glucose and strong for protein and fats.
-The egg yolk(egg cell) tested positive for most tests, positive for glucose and starch but negative for proteins and lipids.
Reflection: This lab I liked a lot because I loved working in the chemistry lab and testing different substances with different chemicals. I am just fascinated with the way molecules work to make up everything we know about life and science. My partner and I worked together to get the job done right and get the correct results for the tests. I am very excited for this year and am looking forward to more exciting labs to do in the future.
Thank you STEM Marin!
-The egg whites tested positive for all tests but tested weakly for glucose and strong for protein and starch.
-The egg membrane tested positive for all tests, weak for glucose and strong for protein and fats.
-The egg yolk(egg cell) tested positive for most tests, positive for glucose and starch but negative for proteins and lipids.
Reflection: This lab I liked a lot because I loved working in the chemistry lab and testing different substances with different chemicals. I am just fascinated with the way molecules work to make up everything we know about life and science. My partner and I worked together to get the job done right and get the correct results for the tests. I am very excited for this year and am looking forward to more exciting labs to do in the future.
Thank you STEM Marin!