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T e sting for Biological Macromolecules. Biology Ms. Haut. Benedict’s Test for Monosaccharides. Add 1 ml (10 drops) of Benedict’s solution to the test tube. Add 8 drops of sample solution to a test tube. Heat the mixture in a boiling water bath for 10 minutes. negative positive.
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Testing for Biological Macromolecules Biology Ms. Haut
Benedict’s Test for Monosaccharides • Add 1 ml (10 drops) of Benedict’s solution to the test tube. • Add 8 drops of sample solution to a test tube. • Heat the mixture in a boiling water bath for 10 minutes. negative positive
http://www.umanitoba.ca/faculties/science/biological_sciences/lab2/images/BenedictsTest-1.jpghttp://www.umanitoba.ca/faculties/science/biological_sciences/lab2/images/BenedictsTest-1.jpg
Initial Color Final Color http://media.photobucket.com/image/benedict%252527s%20test/sapphirex/Char009.jpg http://media.photobucket.com/image/benedict%252527s%20test/sapphirex/Char012-2.jpg
Lugol’s (Iodine) Test for Polysaccharide • Place a 1 mL of the sample solution into a test tube. • Add 5 drops of Lugol’s solution (IKI) to the test tube. • Swirl the test tube to mix. • If the solution turns bluish-black in color, you will know that polysaccharide is present. positive negative http://iws.ccccd.edu/biopage/BioLab/Unit%205/Starch%20test.jpg
http://www.webexhibits.org/causesofcolor/images/content/emerald/DSC03426Z.jpghttp://www.webexhibits.org/causesofcolor/images/content/emerald/DSC03426Z.jpg Note the change of the iodine to black on the potato (right) but not the apple (left). Potato contains starch, but apple does not.
Biuret Test for Proteins • Add 1 ml (10 drops) of Biuret reagent to the test tube. • Put 1 ml of sample in a test tube. • If the solution turns purple in color, you will know that protein is present. http://faculty.clintoncc.suny.edu/faculty/michael.gregory/files/bio%20101/bio%20101%20laboratory/chemical%20composition%20of%20cells/biuret.jpg Positive
Paper Test for Fats • Using the spatula, smear some fat onto a piece of plain paper. Ensure that the paper is not glazed or waxed. • Hold the paper up to the light or window, attempting to look through the spot formed by the fat. • If a greasy spot remains after the paper dries, fats are present.
Sudan III Test for Fats • Place 1 ml of your sample into a test tube. • Place 1 drop of Sudan III solution into your sample. • Swirl the test tube to mix. • If the solution stains red, fats are present. http://biology.unm.edu/ccouncil/Biology_124/Images/sudanIVtest.jpeg