classes of biological molecules

Human Biology Lab 2 Name___________________


Pre-Lab Questions

Question 1:

For the four main classes of biological molecules and fill in the monomer.

Molecule Name Monomer, if applicable
Proteins (polypeptides)  
Nucleic Acids  


Question 2:

Based on what you know about these foods, which biological compound(s) (of the ones we are testing for) do you hypothesize will be present (lipids, starch, sugar, and/or protein)?



White grape juice?

Egg white?



During the following experiment you will be conducting two different types of tests, testing for lipids and a type of carbohydrates, starch. These tests will determine the compounds present in four different unknowns. You will be selecting these unknowns from your own pantry or fridge. You test or will be given the results of a known positive control and a negative control. A positive control is a known strong positive result for the macromolecule being tested. If the unknown solutions look like the positive control result, then that unknown solution is positive for that macromolecule. A negative control is a known negative result for the macromolecule being tested. If the unknown solution looks like the negative control result, then the unknown solution is negative for that macromolecule.


When selecting the foods or drinks you will test, keep in mind the first test, Testing for Lipids, you need the solutions to be liquid and light in color, if too dark it will be hard to tell the results. Some ideas for solutions to test are, juice (from the bottle or you could juice from the fruit), milk, milk alternative, coffee creamer, light colored soup broth, beaten up egg white, or another item you have on hand. For the Testing for Starch test you can use the same solutions used in the other test or you could select solid food options as well. Some ideas for the second test other than listed above are, bread, cereal, crackers, fruit, vegetables, or another food source you have on hand. You will be looking for a color change for when testing for starch so make sure the selected is light in color to easily detect the color change.

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