3.3: Molecules of Life
- Page ID
- 94077
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Burn Test
There are multiple ways this test can be run with a class:
Option 1: Have all student groups test all samples.
Option 2: Have all student groups test one sample (recommended sample: sugar) and have the other samples pre-prepared and students interpret the pre-prepared results.
Option 3: Instructor demonstrates one sample (recommended sample: sugar) and all other samples are pre-prepared and students interpret the results.
Option 4: All samples are pre-prepared and students interpret the results.
Consider which option you are choosing when determining the quantities of materials you will need below.
Preparation
- If you choose one of Options 2, 3, or 4 above, prepare the burn test as follows:
- Place a small amount of each substance in its own separate test tube (baking soda, hair, salt, starch, sugar, vegetable oil, water), preferably a screw-top test tube that can be re-used semester after semester.
- Wear safety goggles. Without a cap or top on the test tube, place the bottom of the test tube in the flame of a Bunsen burner while the opening of the test tube is facing away from you (you only need to do this for the organic samples since the inorganic samples will not burn). You may want to do this in a fume hood.
- Continue burning until the organic samples turn black (this can take a while for oil - just persist).
- Once cool, add caps or tops to the test tubes
Materials
- If you choose option 1 or 2, make sure to have the following on hand:
- test tubes (enough for each sample students will test per group)
- Bunsen burners
- test tube holders
- safety goggles or safety glasses
- the substances that will be tested: baking soda, hair, salt, starch, sugar, vegetable oil, water
- droppers to transfer liquid samples
- spoons or other utensils to transfer solid samples
- test tube racks (enough for 1 per group)
Building Monomers of Biological Molecules
Materials
- organic molecular modeling sets (enough for each student to have one or to share with another student)
Foods & their Biological Molecules
Preparation
The day of or the night before the lab, create food item suspensions as follows:
- add pieces of green banana to a blender and add DI or distilled water
- puree until homogenous
- transfer solution to storage container
- clean blender
- repeat steps 2-5 using black banana, chicken meat (muscle), and egg
Materials
- blended suspensions of green banana, black banana, chicken meat, egg
- five test tubes per group
- labeling tape
- labeling markers
- safety goggles or safety glasses (1 per student)
- test tube rack (1 per group)
- droppers (2-3 per food suspension)
- DI or distilled water
- biuret reagent in dropper bottles (1 for every two groups - groups can share)
- Benedict's solution in dropper bottles (1 for every two groups - groups can share)
- hot plates with beakers containing boiling water or almost boiling water (1 for every two groups - groups can share)
- iodine in dropper bottles (1 for every two groups - groups can share)
- brown paper or brown paper towels
- chemical waste container (biuret and Benedict's waste - can be disposed of in the same container)