Laboratory 2A: "Dissecting" a "Cell" and Examining Its Components
Purpose:What are positive indicator tests for proteins and fats? Do parts of an egg test positive for protein, carbohydrate and/or fat?
Materials:
Eggs Tubes, glass, 13x100 mm Gelatin
Beaker, 250 mL Peg racks for 13x100 mm tubes Biaret Solution
White vinegar Glucose (dextrose)
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 handles
Beaker, 100 mL Lugol's Iodine Solution Trays, plastic
Pipets, 5 mL Vortex mixer
Pipet pump, green
Procedure:
Part 1: Separating Cell Structure
1. Place and uncooked egg into a beaker of white vinegar. Label and cover it with plastic wrap. Leave it for 24 to 28 hours. While the shell dissolves proceed to part 2.
2. After 24 to 28 hours, the shell should have dissolved in the vinegar (acetic acid). Pick up the egg with the spoon and rinse with water.
3. Place the egg in a beaker of 5% NaCl solution for 24 hours.
4. Rinse off the egg and then place in a beaker of distilled water for 24 hours.
5. Then slice the egg open and let the egg whites drip into a 100 mL beaker.
6. place egg yolk in another beaker and set aside egg membranes.
Part 2: Testing Standard Solutions
Monosaccharide Indicator Standard Test:
1. Mix 2 mL of 2% glucose solution with 2 mL of Benedict's Solution. Put on heat for 2 minutes in a 250 mL beaker (100 mL of water filled with 100 degree water and the mixture.
2. Mix 2 mL of deionized water in a test tube with 2 ml of Benedict;s solution. Heat in a hot bath (100 mL of water in 250 mL beaker at 100 degrees.
Starch Indicator Standard Test:
1. Mix 2 mL of well mixed starch suspension with 0.25 mL of Lugol's iodine. Gently swirl to mix.
2. Mix Lugol's iodine ( 0.25 mL) with deionized water (2 mL) in the same quantities. Gently swirl.
Protein Indicator Standard Test:
1. Put 2 mL of gelatin and 0.5 mL Biaret Solution Record color change after 30 seconds.
2. Mix 2 mL of deionized water into a test tube with 0.5 mL of 10% NaOH. Then add 0.25 mL of 5% CuSO4 and mix. Record color change after 30 seconds.
Lipid Indicator Standard Test:
1. Mix 60 uL of Sudan IV and 2 mL of the sample. Red is a negative test and orange is a positive test.
Part 3: Molecular Composition of Egg Components
1. Use same indicator tests for part 2 but substitute each egg component to be tested.
2. record results on data table.
3. Give each test a roman numeral rating and describe the color changes.
Data/Results
Part 1:
Day 1: The egg was dipped in vinegar. The chemicals involved in the reactants and products that dissolve the egg were CaCO3 + CH3COOH and then as the reaction progress they became H2CO3 + H2O + CO2.
Day 2: Shell was dissolved. Its was put in salt water.NaCl inside egg. H2O outside egg.
Day 3: Egg set in water. H2O absorbs more water. It got bigger. It busted open once cut.
Part 2:
Purpose:What are positive indicator tests for proteins and fats? Do parts of an egg test positive for protein, carbohydrate and/or fat?
Materials:
Eggs Tubes, glass, 13x100 mm Gelatin
Beaker, 250 mL Peg racks for 13x100 mm tubes Biaret Solution
White vinegar Glucose (dextrose)
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 handles
Beaker, 100 mL Lugol's Iodine Solution Trays, plastic
Pipets, 5 mL Vortex mixer
Pipet pump, green
Procedure:
Part 1: Separating Cell Structure
1. Place and uncooked egg into a beaker of white vinegar. Label and cover it with plastic wrap. Leave it for 24 to 28 hours. While the shell dissolves proceed to part 2.
2. After 24 to 28 hours, the shell should have dissolved in the vinegar (acetic acid). Pick up the egg with the spoon and rinse with water.
3. Place the egg in a beaker of 5% NaCl solution for 24 hours.
4. Rinse off the egg and then place in a beaker of distilled water for 24 hours.
5. Then slice the egg open and let the egg whites drip into a 100 mL beaker.
6. place egg yolk in another beaker and set aside egg membranes.
Part 2: Testing Standard Solutions
Monosaccharide Indicator Standard Test:
1. Mix 2 mL of 2% glucose solution with 2 mL of Benedict's Solution. Put on heat for 2 minutes in a 250 mL beaker (100 mL of water filled with 100 degree water and the mixture.
2. Mix 2 mL of deionized water in a test tube with 2 ml of Benedict;s solution. Heat in a hot bath (100 mL of water in 250 mL beaker at 100 degrees.
Starch Indicator Standard Test:
1. Mix 2 mL of well mixed starch suspension with 0.25 mL of Lugol's iodine. Gently swirl to mix.
2. Mix Lugol's iodine ( 0.25 mL) with deionized water (2 mL) in the same quantities. Gently swirl.
Protein Indicator Standard Test:
1. Put 2 mL of gelatin and 0.5 mL Biaret Solution Record color change after 30 seconds.
2. Mix 2 mL of deionized water into a test tube with 0.5 mL of 10% NaOH. Then add 0.25 mL of 5% CuSO4 and mix. Record color change after 30 seconds.
Lipid Indicator Standard Test:
1. Mix 60 uL of Sudan IV and 2 mL of the sample. Red is a negative test and orange is a positive test.
Part 3: Molecular Composition of Egg Components
1. Use same indicator tests for part 2 but substitute each egg component to be tested.
2. record results on data table.
3. Give each test a roman numeral rating and describe the color changes.
Data/Results
Part 1:
Day 1: The egg was dipped in vinegar. The chemicals involved in the reactants and products that dissolve the egg were CaCO3 + CH3COOH and then as the reaction progress they became H2CO3 + H2O + CO2.
Day 2: Shell was dissolved. Its was put in salt water.NaCl inside egg. H2O outside egg.
Day 3: Egg set in water. H2O absorbs more water. It got bigger. It busted open once cut.
Part 2:
Part 3:
Data Analysis:
Positive indicator tests are test in which a substance is inserted into a mixture and a certain result will tell if the inserted test is negative or positive. Some parts of an egg test positive for all tests but the membrane is mainly glucose. There were also many problems with the tests we conducted and some of the error in those test could be due to measurement error and/or error due to mixing different chemicals in the pipets. A variation of this lab could be to add in other chemicals to test for certain types of fat. Another application for the indicator test could be to see if someone has certain kind of disease.
Reflection:
In this lab the most interesting thing to me was boiling the test tubes and seeing the mixture change colors. Watching the chemical reaction take place is very interesting. My partner and I collaborated very well. Work was shared equally and efficiency was used. Next time I would move my notebook to a safer place so that it was not only spilled on once but twice by chemicals and egg white. Overall this lab was fun and I would do it again at higher, more complicated level.
Positive indicator tests are test in which a substance is inserted into a mixture and a certain result will tell if the inserted test is negative or positive. Some parts of an egg test positive for all tests but the membrane is mainly glucose. There were also many problems with the tests we conducted and some of the error in those test could be due to measurement error and/or error due to mixing different chemicals in the pipets. A variation of this lab could be to add in other chemicals to test for certain types of fat. Another application for the indicator test could be to see if someone has certain kind of disease.
Reflection:
In this lab the most interesting thing to me was boiling the test tubes and seeing the mixture change colors. Watching the chemical reaction take place is very interesting. My partner and I collaborated very well. Work was shared equally and efficiency was used. Next time I would move my notebook to a safer place so that it was not only spilled on once but twice by chemicals and egg white. Overall this lab was fun and I would do it again at higher, more complicated level.