Lab 2A: Dissecting a cell + examining its components
Purpose
Testing positive indicator tests for proteins, carbohydrates, and fats. Do parts of an egg test positive for protein, carbohydrate, and/or fat?
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 mL
peg racks for 13x100 mL tubes
glucose
benedict's solution
hot plate stirrer
test tube holder
starch, soluble
lugol's iodine solution
vortex mixer
gelatine
sodium hydroxide
cupric sulfate 5-hydrate
oil
sudan IV solution
scalpel handels, #4
scalpel blades, #22, for #4 handles
trays, plastic
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 mL
peg racks for 13x100 mL tubes
glucose
benedict's solution
hot plate stirrer
test tube holder
starch, soluble
lugol's iodine solution
vortex mixer
gelatine
sodium hydroxide
cupric sulfate 5-hydrate
oil
sudan IV solution
scalpel handels, #4
scalpel blades, #22, for #4 handles
trays, plastic
PROCEDURE, part 1: SEPARATING cell strucrures
1. Place uncooked egg into a beaker of the white vinegar. Label and cover it with plastic wrap. Leave it for one to two days. while the shell is dissolving, proceed to part #2.
2. After one to two days, the shell should have dissolved in in the white vinegar in the beaker. Gently pick up the egg with the slotted spoon and rinse in water in order to remove the vinegar left behind. A chemical - reaction has happened here. What were the chemicals involved as reactants and products?
3. Feel the outer membranes of the cell with your fingers. The outer membrane, which is different from the membrane around the yolk, provides a decent model of the membrane of a cell. They are thin and flexible, and permeable to some substances. In order to verify that the cell that water can enter and leave the cell easily, place the egg in a beaker of 5% NaCl solution for one day. What could have caused the change in appearance?
4. Gently rinse the egg with water again. Place the egg in a beaker of distilled water for one day. Describe the change in the appearance of the egg after 24 hours. What caused the change?
5. To retrieve the egg cell, gently slice open the egg's membranes and let the egg white drip through the slots in the spoon into a 100 mL beaker. Try to get all the egg white into a beaker without piercing the yolk.
6. Place the yolk into another beaker, and set aside the egg membrane.
2. After one to two days, the shell should have dissolved in in the white vinegar in the beaker. Gently pick up the egg with the slotted spoon and rinse in water in order to remove the vinegar left behind. A chemical - reaction has happened here. What were the chemicals involved as reactants and products?
3. Feel the outer membranes of the cell with your fingers. The outer membrane, which is different from the membrane around the yolk, provides a decent model of the membrane of a cell. They are thin and flexible, and permeable to some substances. In order to verify that the cell that water can enter and leave the cell easily, place the egg in a beaker of 5% NaCl solution for one day. What could have caused the change in appearance?
4. Gently rinse the egg with water again. Place the egg in a beaker of distilled water for one day. Describe the change in the appearance of the egg after 24 hours. What caused the change?
5. To retrieve the egg cell, gently slice open the egg's membranes and let the egg white drip through the slots in the spoon into a 100 mL beaker. Try to get all the egg white into a beaker without piercing the yolk.
6. Place the yolk into another beaker, and set aside the egg membrane.
Procedure, part 2: testing standard solutions
Monosaccharide Indicator Standard Test
1. Test for glucose by mixing 2 mL of of a 2% glucose solution in a test tube with 2 mL of Benedict's solution. Heat for 2 minutes in boiling water (100mL of water in a 250mL beaker). Record all color changes and the length of time they appear.
2. Test for water by mixing 2mL of deionized water with 2mL of Benedict's solution in a test tube. Heat for 2 minutes in boiling water. Record all color changes and the amount of time for each color to appear.
Starch Indicator Standard Test
1. In a test tube, mix 2mL of well-mixed starch suspension with 0.25mL of Lugol's iodine. Gently swirl to mix. Record color change.
2. In a test tube, mix 2mL of deionized water with 0.25mL of Lugol's iodine. Gently swirl to mix. Record color change.
Protein Indicator Standard Test
1. Place 2mL of gelatin solution in a test tube. Add 0.5mL of 10% NaOH and gently vortex to mix. Add 1mL of Biuret solution. The NaOH and CuSO4 is called Biuret reagant. Mix and record color change after 30 seconds.
2. Place 2mL of deionized water in a test tube. Add 0.5 mL of 10% NaOH and mix. Add 0.25mL of 5% CuSO4. Mix and record color change after 30 seconds.
Lipid Indicator Standard Test.
Add 60 ml of sudan iv solution to 2mL of sample. Gently mix. Red is nagative and orange is positive.
1. Test for glucose by mixing 2 mL of of a 2% glucose solution in a test tube with 2 mL of Benedict's solution. Heat for 2 minutes in boiling water (100mL of water in a 250mL beaker). Record all color changes and the length of time they appear.
2. Test for water by mixing 2mL of deionized water with 2mL of Benedict's solution in a test tube. Heat for 2 minutes in boiling water. Record all color changes and the amount of time for each color to appear.
Starch Indicator Standard Test
1. In a test tube, mix 2mL of well-mixed starch suspension with 0.25mL of Lugol's iodine. Gently swirl to mix. Record color change.
2. In a test tube, mix 2mL of deionized water with 0.25mL of Lugol's iodine. Gently swirl to mix. Record color change.
Protein Indicator Standard Test
1. Place 2mL of gelatin solution in a test tube. Add 0.5mL of 10% NaOH and gently vortex to mix. Add 1mL of Biuret solution. The NaOH and CuSO4 is called Biuret reagant. Mix and record color change after 30 seconds.
2. Place 2mL of deionized water in a test tube. Add 0.5 mL of 10% NaOH and mix. Add 0.25mL of 5% CuSO4. Mix and record color change after 30 seconds.
Lipid Indicator Standard Test.
Add 60 ml of sudan iv solution to 2mL of sample. Gently mix. Red is nagative and orange is positive.
procedure, part 3: molecular composition of egg components
1. Conduct each indicator test as described in step two, but substitute each egg component to be tested for the sugar, fat, or protein in the test. Change only one variable per test.
2. Record the results of testing all three egg parts for all four molecules in a data table.
3. Number each test and record color changes.
2. Record the results of testing all three egg parts for all four molecules in a data table.
3. Number each test and record color changes.
results: Part one
Day one: We placed the egg in vinegar.
Day two: Shell was dissolved, we placed the egg in salt water. The salt went into the egg and the water left the egg. Our egg got smaller due to lack of water.
Day three: After 24 hours in distilled water the egg had grown larger again. We cut it open and our egg was pressurized so it exploded due to the large amount of water inside of the membrane.
Day two: Shell was dissolved, we placed the egg in salt water. The salt went into the egg and the water left the egg. Our egg got smaller due to lack of water.
Day three: After 24 hours in distilled water the egg had grown larger again. We cut it open and our egg was pressurized so it exploded due to the large amount of water inside of the membrane.
Results: part two
Results: part three
Data analysis
As a result of our tests, we can conclude that some egg components do test positive for either fats, proteins, starch and glucose. We learned about different indicators for each of these components and then tested them with the different parts of an egg.
Reflection
I thought that it was very interesting to be able to see a egg without its shell and only its membrane. I also found it interesting to be able to compose tests allowing me witness the chemical reaction showing that egg cell components contained different chemicals. My partner an I collaborated very well and i thought that we each did an equal amount of work. We worked well together because we understand each other and are both good at collaboration. We both have strengths and weaknesses and we helped each other throughout this lab with what we each needed help on. This lab helped both us learn about the components of an egg, but more importantly helped us learn how to perform indicator tests and how to work with others.