Lab #3 - Chemical Composition of Cells.pptx - 1 Lab #3 –...

BIOL 1106
Professor Stinemetz
Lab #3 – Chemical Composition
of Cells
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Introduction
In living organisms and in common substances that we use daily,
the large biological molecules – proteins, lipids, nucleic acids,
and carbohydrates – are present. By utilizing different chemical
reagents, and for one experiment a simple brown paper towel test,
you will be able to determine (with the exception of nucleic acids),
if these large macromolecules are present in a variety of
substances.
In all the experimental procedures water will be the control . A
control is a substance included in the experiment that we already
know does not contain the macromolecule we are testing for. This
is important to ensure the accuracy of the experiment.

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Introduction
A different reagent will be used for each molecule we are testing
for. This reagent will have certain chemical properties, and there
will be a visible change in the reagent when it interacts with the
molecule we are testing for. A positive test for a molecule will be
indicated by a color change as compared with the control
(meaning the substance we are testing for is present). If the
reagent is the same color as the control, the result is a negative
test, and we know that the substance we are testing for is not
present.