Biology A
- Feeding Frenzy
- Introduction
- Methods and Materials
- Data and Conclusions
- Discussion
Introduction
Purpose
To determine what is in the food we eat using a qualitative test.
Question
What macromolecules/biomolecules are found in an m&m cookie?
Background
Lipids: Fats, lipid fat are used to encase cells
Starch: Carbohydrates, found in many foods like pasta or bread
Sugar: Quick Energy, found in many sweet foods
Protein: Break food down amino acids, found in meats
Predicted Outcome
We predicted that all macromolecules would be present in the cookie. Weassumed this because of past nutrition labels we had read on cookies,which stated the cookie had fats, proteins, sugars, and carbohydratesinside.
Hypothesis
If we test our cookie for lipids, starch, sugar, and protein, we willfind that the cookie does indeed have lipids, starch, sugar, andprotein.
Methods and Materials
Materials
Safety Goggles Beakers Hot Plate
Disposable Gloves Benedict’s Solution Gram Scale
Test Tubes Iodine Measuring spoon
Test Tube Clamp Biuret reagent Karo Syrup (glucose)
Test Tube Rack Sudan III reagent Laundry Starch
Eye Dropper Brown Paper Bag Egg Whites
Glass Stirring Rod Fork, knife, spoon Vegetable Oil
Distilled Water Plastic Cups Blender
Mortar and pestle graduated cylinder M&m Cookie
Procedure
Prelab
- Brainstorm what foods you want to test and for what macromolecules you are testing.
- Complete the 15 Questions for Investigation.
- Decide who is going to bring what foods. Hint: lighter color foods yield more accurate results.
Lab
- Create positive and negative test controls for each macromolecule test.
a. Lipids
i.PositiveControl-Fill a test tube 4/5 full with vegetable oil. Pour 10 drops ofSudan III into the test tube with the vegetable oil. Label the testtube as “positive control lipids” using masking tape and place in thetest tube rack.
ii. Negative Control-Fill a test tube 4/5 fullwith distilled water. Pour 10 drops of Sudan III into the test tubewith the water. Label the test tube as “negative control lipids” usingmasking tape and place in the test tube rack.
b. Sugar
i. Positive Control-Mix 10g of Karo Syrup with 100mL of distilled water ina beaker. Fill a test tube 4/5 with the solution. Pour 10 drops ofBenedict’s Solution into the test tube. Clean the beaker. Fill thebeaker full of water. Place the beaker full of water on a hot plateand turn the hotplate on high. Place the test tube in the beaker fullof water and boil for 5 minutes. Label the test tube as “positivecontrol sugar” using masking tape and place in the test tube rack.
ii. Negative Control-Fill a test tube 4/5 full of distilled water. Pour 10drops of Benedict’s Solution into the test tube. Fill a beaker full ofwater. Place the beaker full of water on a hot plate and turn thehotplate on high. Place the test tube in the beaker full of water andboil for 5 minutes. Label the test tube as “negative control sugar”using masking tape and place in the test tube rack.
c. Protein
i. Positive Control-Mix 1g of egg white powder (or albumen) with 100mL ofdistilled water in a beaker using a glass stirring rod until all of thepowder is dissolved. Pour the solution into a beaker until the beakeris 4/5 full. Pour 10 drops of Biuret reagent into the test tube withthe solution. Label the test tube as “positive control protein” usingmasking tape and place in the test tube rack.
ii. NegativeControl- Fill a test tube 4/5 full with distilled water. Pour 10 dropsof Biuret reagent into the test tube with the water. Label the testtube as “negative control protein” using masking tape and place in thetest tube rack.
d. Starch
i. Positive Control-Mix 1g ofcorn starch with 100mL of distilled water in a beaker using a glassstirring rod until all of the powder is dissolved. Pour the solutioninto a beaker until the beaker is 4/5 full. Pour 10 drops of iodinereagent into the test tube with the solution. Label the test tube as“positive control starch” using masking tape and place in the test tuberack.
ii. Negative Control- Fill a test tube 4/5 full withdistilled water. Pour 10 drops of iodine reagent into the test tubewith the water. Label the test tube as “negative control starch” usingmasking tape and place in the test tube rack.
Make the foods you are testing into a solution.
e. This can be done with a mortar and pistil or a blender. Place yourcrunched up food into a beaker. Add water to your food in the beaker tomake it into a solution. Filter the chunks out by pouring the solutionthrough a screen and/or cheesecloth into another beaker.
Pour thefood solution into as many test tubes as the number of tests you areperforming. For example, if you are testing for starch, sugar,protein, and lipids you will need four test tubes. Label each test tubewith the food that is being tested and the macromolecule you aretesting for using masking tape.
Place 10 drops of the appropriate reagent in the appropriate test tube.
f. Sugar - Benedict’s Solution – must be heated with food in order to produce a result
g. Starch - Iodine
h. Protein - Biuret reagent
i. Lipid - Sudan III reagent
Compare your results to the positive and negative test controls. Record your data in a data table
Complete a lab report by following the lab report template. All sections are required except calculations.
Type up your lab report using google docs and invite all interested parties.
Post your lab report on your unit 2 webpage.
Data and Conclusions
Observations
Taste: Bad
Appearance: Foggy, Crumbly, Thick, Chunky, Rainbow
Smell: Sweet, Doughy
Texture: Squishy, Moist
In solution: Changed color, chunked, 'gross'
Data Table
Graph
Discussion
Results
Thecookie solution changed color, and when we took the 4 solutions for all4 variables to the control group, we matched up the colors andmacromolecules. Some of the colors were a bit off, because of how thecookie in the solution clouded up the water, while the controls werenot mixed with any sort of fogging food. But, with this uncertainty wewere still able to see that all of the macromolecules (protein, sugar,starch, and lipids) were positive.
Conclusion
Thiscookie had all four macromolecules: positive protein, sugar, starch,and lipids. The uncertainties were that the color of the solution(s)may have been affected by the cookie itself, and that there may havebeen more M&M's in one solution than there were in another. Plus,the negative lipid control seemed to have dissapeared, and even thoughthe cookie certainly had lipids, we should have checked anyway.
Thisinformation, unfortunately, is only qualitive. If we had a method ofrecording the exact amount of each macromolecule in every solution,then maybe we would have gotten more accurate results.
