BiologyMs. Haut

1. Add 1 ml (10 drops) of Benedict’s solution to the test tube.

2. Add 8 drops of sample solution to a test tube.

3. Heat the mixture in a boiling water bath for 10 minutes or until the control turns orange.

                                                

      negative positive

http://media.photobucket.com/image/benedict%252527s%20test/sapphirex/Char009.jpg

http://media.photobucket.com/image/benedict%252527s%20test/sapphirex/Char012-2.jpg

Initial Color Final Color

http://www.umanitoba.ca/faculties/science/biological_sciences/lab2/images/BenedictsTest-1.jpg

1. Place a 1 mL of the sample solution into a test tube.

2. Add 5 drops of Lugol’s solution (IKI) to the test tube.

3. Swirl the test tube to mix.

4. If the solution turns bluish-black in color, you will know that polysaccharide is present.

                                                

       positive negative

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Note the change of the iodine to black on the potato (right) but not the apple (left). Potato contains starch, but apple does not.

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1. Add 1 ml (10 drops) of Biuret reagent to the test tube.

2. Put 1 ml of sample in a test tube.

3. If the solution turns purple in color, you will know that protein is present.

Positive

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1. Using the spatula, smear some fat onto a piece of plain paper. Ensure that the paper is not glazed or waxed.

2. Hold the paper up to the light or window, attempting to look through the spot formed by the fat.

3. If a greasy spot remains after the paper dries, fats are present.

1. Place 1 ml of your sample into a test tube.

2. Add 1 ml of distilled water to the test tube.

3. Place 1 drop of Sudan III solution into your sample.

4. Swirl the test tube to mix.

5. If the solution stains red, fats are present.

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Which test produced these results?• Benedict’s Test

Which macromolecules does it test for?• Monosaccharides

Which test tubes indicates a positive result? How do you know?

A B

Which test produced these results?• Sudan III Test

Which macromolecules does it test for?• Lipids

Which test tubes indicates a positive result? How do you know?A B

Which test produced these results?• Lugol’s Test

Which macromolecules does it test for?• Polysaccharides

Which test tubes indicates a positive result? How do you know?A B

Which test produced these results?• Biuret Test

Which macromolecules does it test for?• Proteins

Which test tubes indicates a positive result? How do you know?

A B C D