Introduction:

Safety: / / Hot:
/ / /
  • Caution will be needed as we will be working with chemicals and heat.
  • Safety glasses and aprons will be worn until clean up of lab is complete.
  • Tongs or test tube clamps will be used to handle test tubes in the water bath.
  • Place all broken glass in the appropriate container.
  • Biuret’s solution is caustic (basic) and should be rinsed off if it comes in contact with your skin.
  • Place your belongings at the front of the room and push all chairs in to keep aisles clear.
  • Wash hands after lab and clean up are completed.

Procedure:

Part 1: Establishing Standards to know what a positive test for each nutrient looks like

A.  Lipids/Fats

·  Place 1-2 drops of the sample on a piece of brown paper bag.

·  Shake off any excess liquid.

·  Let dry for 10-15 minutes.

·  Observe/check for color change.

·  A positive result will be an oily or wet spot on the brown bag.

B.  Glucose/Simple Sugars

·  Fill a clean test tube with 1 mL of the sample to be tested.

·  Add 5-7 drops of Benedict’s Solution.

·  Heat test tube in a hot water bath for 2-3 minutes.

·  Check/Record color change.

·  A positive result will be yellow, orange or green solution.

C.  Starch/Carbohydrates

·  Fill a clean test tube with 1 mL of the sample to be tested.

·  Add 1 drop of iodine.

·  Check/Record color change.

·  A positive result will be a royal blue/purple to black solution.

D.  Protein

·  Fill a clean test tube with 1 mL of the sample to be tested.

·  Add 5-7 drops of Biuret solution.

·  Check/Record color change.

·  A positive result will be a pink or purple solution.

Data Table 1 – Indicator Data

Brown Bag - Lipids / Benedict’s - Sugar / Iodine - Carbohydrates / Biuret’s - Protein
Sample Name
Positive Indicator Color

Part 2: Testing Stomach Contents

1.  Take a small sample of each person’s stomach contents back to your station to test for the presence of the following four substances (Fats, Sugars, Carbohydrates, & Protein).

2.  Repeat the procedure stated in Part 1 for each person’s stomach juice. (Test for fats, test for sugars, test for carbohydrates, test for protein using the same procedure as stated above.)

3.  Record your results in the Data Table 2.

Data Table 2: Stomach Contents Results

Stomach Contents Sample From Victim / Brown Bag - Lipids / Benedict’s - Sugar / Iodine - Carbohydrates / Biuret’s - Protein
1
2
3
4

Investigation Follow-Up

While you were testing evidence in the Toxicology Lab, the police followed up with the catering company the Parkers chose to cater their event. The Yellow Jacket Catering Company that supplied food was known to hire former convicts to work in their kitchens. Each person in the hors d’oeuvres department is a specialist and known for specific hors d’oeuvres. As various trays and platters are completed and ready for delivery, the preparer signs off that the job was completed. Therefore, for each item on the food patter, there is a record of who prepared the food. The documents showed that the following individuals signed off on the various hors d’oeuvres served at the party. (Coincidentally, all of the individuals were former convicts prosecuted by Mr. Parker himself and all had reason to seek revenge.)

Part 3: Who dunn it?

·  Based on the chart above and your analysis of the stomach contents of each victim, determine what each victim ate at the party and list in Data Table 3.

Data Table 3: Victim’s Last Meal

Victim / Hors d’oeuvres Eaten
1
2
3
4

Analysis Questions:

1.  What food type(s) did ALL the victims have in their stomachs?

2.  Based on the evidence collected by the police and your testing, who do you think poisoned the food at the Parker’s party?

3.  Completely explain your answer to #2. (Using scientific evidence, how do you know who dunn it?)

4.  What are the functions of carbohydrates, lipids and proteins in a living cell?

5.  Write a lab summary paragraph; include information about the indicators and the 3 biomolecules tested in this laboratory (carbohydrates, lipids, and proteins).