lab 2a
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 protein, carbohydrate, and/or fat?
Materials list -
eggs tubes, glass, 13x100 mm gelatin
beaker, 250 mL peg racks for 13x100 mm sodium hydoxide
white vinegar tubes cupric sulfate 5-hydrate
plastic wrap glucose(dextrose) oil
slotted spoon Benedict's solution sudan IV solution
sodium chloride hot plate stirrer scalpel handles, #4
distilled water test tube holder scalpel blades, #22, for
beaker, 100 mL starch, soluble #4 handles
pipets, 5 mL Lugol's iodine solution trays, plastic
pipet pump, green vortex mixer
Materials list -
eggs tubes, glass, 13x100 mm gelatin
beaker, 250 mL peg racks for 13x100 mm sodium hydoxide
white vinegar tubes cupric sulfate 5-hydrate
plastic wrap glucose(dextrose) oil
slotted spoon Benedict's solution sudan IV solution
sodium chloride hot plate stirrer scalpel handles, #4
distilled water test tube holder scalpel blades, #22, for
beaker, 100 mL starch, soluble #4 handles
pipets, 5 mL Lugol's iodine solution trays, plastic
pipet pump, green vortex mixer
Procedure -
Part 1: separating cell structures
1. Put 1 egg uncooked into white vineager in a beaker. Have a label on it with plastic wrap on top for 24 to 48 hours. Continue to part 2 while shell dissolves.
2. After the time limit, the shell should've dissolved in the vinegar. Lift the egg out with a spoon, rinse it with water.
3. Feel the egg. This provides a good model of a cell membrane. Describe how the egg looks again after 24 hour. How did it get this way?
4. Rinse off the egg with water, put it into a beaker of water for 24 hours. Describe the appearance and why it's this way.
5. Get the egg cell by carefully and gently slice through the eggs membranes. Let the egg white drip into a beaker all the way.
6. Put the yoke into a separate beaker.
Part 2: testing standard solutions
Monosaccharide Indicator Standard Test
1. Test for glucose. In a test tube, mix 2 mL of a 2% glucose (a monosaccharide) solution with 2 mL of benedicts solution. Heat for 2 minutes in a boiling hot water bath (100 mL of water in a 250 mL beaker at 100degrees C) record all color changes and the length of time for each color to appear.
2. Test for water (negative control): In a test tube, mix 2 mL of deionized water with 2 mL of Benedicts solution. Heat for 2 minutes in a boiling hot water bath (100 mL of water in a 250-mL beaker at 100 degrees C). Record all color changes and the amount of time for each color to appear.
Starch Indicator Standard Test
1. Test for starch: in a test tube, mix 2 mL of well mixed starch suspension with 0.25 mL of Lugols iodine. Gently swirl to mix. No heat. Record color change.
2. Test for water(negative contral): In a test tube, mix 2 mL of deionized water with 0.25 mL of Lugols iodine. Gently swirl to mix. NO heat. Record color change.
Part 1: separating cell structures
1. Put 1 egg uncooked into white vineager in a beaker. Have a label on it with plastic wrap on top for 24 to 48 hours. Continue to part 2 while shell dissolves.
2. After the time limit, the shell should've dissolved in the vinegar. Lift the egg out with a spoon, rinse it with water.
3. Feel the egg. This provides a good model of a cell membrane. Describe how the egg looks again after 24 hour. How did it get this way?
4. Rinse off the egg with water, put it into a beaker of water for 24 hours. Describe the appearance and why it's this way.
5. Get the egg cell by carefully and gently slice through the eggs membranes. Let the egg white drip into a beaker all the way.
6. Put the yoke into a separate beaker.
Part 2: testing standard solutions
Monosaccharide Indicator Standard Test
1. Test for glucose. In a test tube, mix 2 mL of a 2% glucose (a monosaccharide) solution with 2 mL of benedicts solution. Heat for 2 minutes in a boiling hot water bath (100 mL of water in a 250 mL beaker at 100degrees C) record all color changes and the length of time for each color to appear.
2. Test for water (negative control): In a test tube, mix 2 mL of deionized water with 2 mL of Benedicts solution. Heat for 2 minutes in a boiling hot water bath (100 mL of water in a 250-mL beaker at 100 degrees C). Record all color changes and the amount of time for each color to appear.
Starch Indicator Standard Test
1. Test for starch: in a test tube, mix 2 mL of well mixed starch suspension with 0.25 mL of Lugols iodine. Gently swirl to mix. No heat. Record color change.
2. Test for water(negative contral): In a test tube, mix 2 mL of deionized water with 0.25 mL of Lugols iodine. Gently swirl to mix. NO heat. Record color change.
Protein Indicator Standard Test 1. Test for protein: place 2 mL of gelatin (protein) solution in a test tube. Wearing goggles and gloves, add 0.5 mL of 10 percent NaOH and gently vortex to mix. add 0.25mL of 5 percent copper sulfate (CuSO 4) and gently mix. The NaOH and CuSO 4 mixture is called Biuret reagent. Mix well. Record results after 30 sec.
2. Test for water (negative control): Place 2 mL of deionized water in a test tube. Wearing goggles and gloves, add 0.5 mL of 10 percent NaOH, and gently vortex to mix. Add 0.25 mL of 5% CuSO 4 and gently mix well. Record results after 30 seconds.
Part 3
1. Conduct each indicator test, as described in part 2, but substitute each egg component to be tested for sugar, starch, protein, or fat in the test. All volumes and test conditions are the same as part 2, only the item tested (the unkowns) is changed. Make sure that you do not add any of the standard solutions.
2. Record the results of testing the egg membranes, the yolk (cell cytoplasm), and egg white for all four molecules on another data table.
3. Give a numerical value to each test result using the system described in the key below table 22, which is based on a comparison with the standard tests. Also include a brief description of color changes.
2. Test for water (negative control): Place 2 mL of deionized water in a test tube. Wearing goggles and gloves, add 0.5 mL of 10 percent NaOH, and gently vortex to mix. Add 0.25 mL of 5% CuSO 4 and gently mix well. Record results after 30 seconds.
Part 3
1. Conduct each indicator test, as described in part 2, but substitute each egg component to be tested for sugar, starch, protein, or fat in the test. All volumes and test conditions are the same as part 2, only the item tested (the unkowns) is changed. Make sure that you do not add any of the standard solutions.
2. Record the results of testing the egg membranes, the yolk (cell cytoplasm), and egg white for all four molecules on another data table.
3. Give a numerical value to each test result using the system described in the key below table 22, which is based on a comparison with the standard tests. Also include a brief description of color changes.
Data/Results
Part 1- CaCO3 + CH3COOH => H2CO3 + H2O + CO2
Day 1. Egg submerged in vinegar
Day 2. Egg in salt water
NaCL went inside egg
H20 went outside of egg
- shell was dissolved
Day 3. Egg in water
when egg had a slit, all insides burst out
Part 2
Part 1- CaCO3 + CH3COOH => H2CO3 + H2O + CO2
Day 1. Egg submerged in vinegar
Day 2. Egg in salt water
NaCL went inside egg
H20 went outside of egg
- shell was dissolved
Day 3. Egg in water
when egg had a slit, all insides burst out
Part 2
Part 3-
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.
Data/Analysis-From completing this lab my partner and I saw the difference from positive and negative results in each of the expirements. Finding what the outcomes of these expirements gave us the answers to the purpose of the lab. I believe that my partner made a few mistakes in this lab, specifically when testing with the parts of the egg. If we did this lab again I would say that my partner and I take more time on our expirements just to make sure that we were doing them correctly.