My notes and thoughts from Biology 111 Lab, for Monday, September 15, 2008. The entire series can be found here.
In this lab, we learned to use reagents to test for the presence of proteins, starch, and sugars, using distilled water as a negative control.
Since distilled water should be straight H2O and nothing else, each time we did a test, we could see what the reagent did in solution without the presence of whatever it was we were testing for.
We worked in groups, and our group consisted of four students.
A. In the first experiment, we tested for the presence of proteins with Biuret reagent, a highly corrosive blue/purply substance. Our Lab Manual and Doc each warned us about its potential hazards, safety precautions, and what to do if we got it on our skin.
We marked four test tubes at the 1 cm level.
1) Test tube 1 we filled to the mark with distilled water. We then added about 5 drops of Biuret reagent. The water turned light blue. This was our negative control to which we could compare the other tubes when the Biuret reagent was added.
Lab continues, below the fold.