All living things contain organic molecules such as lipids, carbohydrates, proteins and acids. In order to detect the presence of carbohydrates, proteins and lipids we have to do experiments. The Iodine test is used to detect the presence of carbohydrates. This test is used to distinguish starch (polysaccharide) from carbohydrates. Reaction between starch and Iodine produce a dark grey, black color and it means that the test is positive. A yellow color means that test is negative. But other polysaccharides may give other colors including blue or red. In order to detect the presence of glucose (monosaccharide) we have to use a Clinitest tablet. Clinitest tablets are usually used for urine sugar testing. If test is positive it produces green color. If test is negative color will be blue. The Biuret test is a chemical test used to the presence of proteins. Biuret reagent is a light blue color solution. The blue reagent turns violet in the presence of proteins. If test is negative color of the solution will not be changed. A lot of lipids function as energy storage. In order to detect presence of lipids we need to do an experiment. The Sudan IV test helps us detect a presence of lipids. As we know lipid molecules do not mixes with water. So if result for reaction is positive color turns red that show us location of lipids.
1) 9 tubes
3) Clinitest tablets
6) Distilled water
7) Salad oil
8) Sudan IV
10) Biuret’s reagent
Experiment 1: Detecting carbohydrates
We label 6 tubes A1, B1, C1, A1, B2, and C2. We add 3 ml of starch in tubes A1 and A2, 3 ml of glucose in tubes B1 and B2, and 3 ml of distilled water in tubes C1 and C2. To A1, B1 and C1 we add 5 drops of Iodine in each tube. In each A2, B2, and C2 tubes we add 1 Clinitest tablet. Experiment 2: Detecting Proteins
We label 2 tubes A and B. In a tube A we add 5 ml of Albumin solution and 5 ml of Starch...
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