Lab 2a : Dismantling a cell and examining it's contents
Purpose: To investigate the contents of animal cells and the materials that they are composed of
Materials:
Eggs Tubes, glass, 13x100 mm Gelatin
Beaker, 250 mL Peg racks for 13x100 mm tubes Biuret Solution
White vinegar Glucose (dextrose) scalpel
Plastic wrap Benedict's Solution sudan IV solution
Slotted spoon Hot plate stirrer
Sodium Chloride Test tube holder
Distilled water Starch, soluble
Beaker, 100 mL Lugol's Iodine Solution
Pipets, 5 mL Vortex mixer
Pipet pump, green Oil solution
Procedure:
Part I: Separating Cell Structures
1. Place an uncooked egg into a labeled beaker of white vinegar. Cover with plastic wrap and let sit for 24 to 48 hours.
2. When shell dissolves, , pick up egg with spoon and examine chemical reaction
3. Feel outer membranes, which provide a good representation of a cell membrane, being permeable. To prove this, leave egg in a solution of 5% NaCl solution for 24 and describe.
4. Gently rinse egg/ water and place egg in distilled water for 24 hours.
5. Collect egg cell by slicing membrane and let egg white drip into 100-mL. beaker.
6. Plaace yolk into another beaker and set aside membranes.
Part II: Testing Standard Solutions
Monosaccharide Indicator Standard test
1. Test for Glucose; mix 2mL. of 2% glucose solution with 2mL. of Benedict's solution and heat for 2 minutes in boiling water bath. Record all color changes and time of appearance.
2. Test for Water; repeat step one, substituting 2% glucose solution with deionized water.
Starch Indicator Standard test
1. Test for Starch; mix 2mL of well-mixed starch suspension with 0.25mL of Lugol's iodine. Mix, but do not heat.
2. Test for Water; Repeat step one, substituting starch suspension with 2mL. of deionized water.
Protein Indicator Standard Test
1. Test for Protein. mix 2mL. of gelatin solution with 1mL. of pre-mixed biuret regent. Mix well and record color change after 30 sec.
2. Test for Water. Repeat step 1 substituting water for
Lipid Indicator Standard Test
1. Test for Lipids. Mix 60 ,ul of Sudan IV solution with 2 mL. of oil solution
2. Test for water and repeat, substitute oil with water.
Part III: Composition of Egg components
1. Repeat all steps of Part II replacing water and test molecules with each of the three egg components (membrane, white and yolk)
2. Record all results on data table, as with part II and describe color change (positive or negative)
Data and results
Day 1: Egg placed in vinegar and shell began dissolve.
CaCO3 and CH3COOH react with egg shell to become H2CO3, H2O and CO2.
Day II: Egg shell dissolved by vinegar and remaining egg is placed in salt solution. Salt solution permeates egg membrane to balance salt concentrations
Day III: Egg placed in water and absorbs it/ expands. Behaves like water balloon when punctured.
Not pleasant
Part II Data Part III Data
Materials:
Eggs Tubes, glass, 13x100 mm Gelatin
Beaker, 250 mL Peg racks for 13x100 mm tubes Biuret Solution
White vinegar Glucose (dextrose) scalpel
Plastic wrap Benedict's Solution sudan IV solution
Slotted spoon Hot plate stirrer
Sodium Chloride Test tube holder
Distilled water Starch, soluble
Beaker, 100 mL Lugol's Iodine Solution
Pipets, 5 mL Vortex mixer
Pipet pump, green Oil solution
Procedure:
Part I: Separating Cell Structures
1. Place an uncooked egg into a labeled beaker of white vinegar. Cover with plastic wrap and let sit for 24 to 48 hours.
2. When shell dissolves, , pick up egg with spoon and examine chemical reaction
3. Feel outer membranes, which provide a good representation of a cell membrane, being permeable. To prove this, leave egg in a solution of 5% NaCl solution for 24 and describe.
4. Gently rinse egg/ water and place egg in distilled water for 24 hours.
5. Collect egg cell by slicing membrane and let egg white drip into 100-mL. beaker.
6. Plaace yolk into another beaker and set aside membranes.
Part II: Testing Standard Solutions
Monosaccharide Indicator Standard test
1. Test for Glucose; mix 2mL. of 2% glucose solution with 2mL. of Benedict's solution and heat for 2 minutes in boiling water bath. Record all color changes and time of appearance.
2. Test for Water; repeat step one, substituting 2% glucose solution with deionized water.
Starch Indicator Standard test
1. Test for Starch; mix 2mL of well-mixed starch suspension with 0.25mL of Lugol's iodine. Mix, but do not heat.
2. Test for Water; Repeat step one, substituting starch suspension with 2mL. of deionized water.
Protein Indicator Standard Test
1. Test for Protein. mix 2mL. of gelatin solution with 1mL. of pre-mixed biuret regent. Mix well and record color change after 30 sec.
2. Test for Water. Repeat step 1 substituting water for
Lipid Indicator Standard Test
1. Test for Lipids. Mix 60 ,ul of Sudan IV solution with 2 mL. of oil solution
2. Test for water and repeat, substitute oil with water.
Part III: Composition of Egg components
1. Repeat all steps of Part II replacing water and test molecules with each of the three egg components (membrane, white and yolk)
2. Record all results on data table, as with part II and describe color change (positive or negative)
Data and results
Day 1: Egg placed in vinegar and shell began dissolve.
CaCO3 and CH3COOH react with egg shell to become H2CO3, H2O and CO2.
Day II: Egg shell dissolved by vinegar and remaining egg is placed in salt solution. Salt solution permeates egg membrane to balance salt concentrations
Day III: Egg placed in water and absorbs it/ expands. Behaves like water balloon when punctured.
Not pleasant
Part II Data Part III Data
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Data Analysis
Indicator tests are used to tell whether a material contains a certain substance. For example, we used a Sudan IV indicator to test the components of an egg for the presence of fat. Of course, there are plenty of opportunities for experimental error. Egg components were difficult to measure accurately, maybe leading to a mismeasurement and an innacurate result. Errors aside, labs like these are useful in the medical field to test patients for unnatural substances, some that could indicate disease.
Reflection
Testing for such specific substances in an egg was easier than I had anticipated. Probably the most simple procedure in chemistry is mixing two chemicals and apparently that is all it takes to test for substances like starch and fat. Not only was testing easy, but collaboration as well. My partner and I worked well together (having done so last year as well) and every test was done quickly and efficiently. On a personal note, I don't think I will be making omlettes any time soon. Having to scrape the tested egg substances out of a test tube may have been a little too much.
Indicator tests are used to tell whether a material contains a certain substance. For example, we used a Sudan IV indicator to test the components of an egg for the presence of fat. Of course, there are plenty of opportunities for experimental error. Egg components were difficult to measure accurately, maybe leading to a mismeasurement and an innacurate result. Errors aside, labs like these are useful in the medical field to test patients for unnatural substances, some that could indicate disease.
Reflection
Testing for such specific substances in an egg was easier than I had anticipated. Probably the most simple procedure in chemistry is mixing two chemicals and apparently that is all it takes to test for substances like starch and fat. Not only was testing easy, but collaboration as well. My partner and I worked well together (having done so last year as well) and every test was done quickly and efficiently. On a personal note, I don't think I will be making omlettes any time soon. Having to scrape the tested egg substances out of a test tube may have been a little too much.