An organic molecule refers the molecules of living things composed of carbon atoms organized in rings or chains on which other elements like gasses (nitrogen, hydrogen, and oxygen) attaches themselves.
Purposes of the experiments
The experiment would test food sample for the presence of organic molecules i.e. proteins, polysaccharides, and sugar.
Question
Would reagent used in this experiment identify the organic molecules?
Hypothesis
Reagents Benedict’s solutions, Biurets solution, and iodine would establish the presence of sugars, proteins, and starch respectively.
Setup of the experiment
Materials
Benedict solution that is a blue in color and contains copper ions. It is used in the laboratory to test for the presence of reducing sugars.
Biuret’s solution that is light blue in color and turns purple in the presence of protein in a solution.
Iodine solution that is a yellow-brownish solution in color and changes to black or blue solution in the presence of starch.
Test tubes
Beakers
Source of heat (heater)
Steps to follow
Get two sets of the test tubes and label them A and B.
Add one cubic centimeter of a glucose solution to test tube A, and water in test tube B.
Take drops of the Benedict’s solution and add them to the solutions in test tubes A and B.
Gently, shake the solution and put the two test tubes in a hot water bath for fifteen minutes.
After fifteen minutes, observe the changes in color and record the result in the table below.
Proceed to prepare two other test tubes and mark them C and D.
In test tube C, add a starch solution and in D, add water.
After that, add a few drops of iodine solution in both test tubes. Shake each of them and observe any color changes. Record the results in the table below.
Prepare another set of test tubes and mark the E and F.
In E, add egg white and water in F.
Put drops of Biuret reagent in both test tubes and shake gently. Observe the color changes. Record the result in the table.
Add a drop of water and oil on a brown paper and add iodine, and observe the results. Record them in the table.
Results of the Experiment
Conclusion
Upon adding Benedict’s solution to the glucose solutions, the color turned to brick red indicating the presence of reducing sugars. The Benedicts reagent separated the sugars from the carbohydrates making them float.
Adding a couple of drops of the Biuret’s reagent in the egg white, it changed to purple, indicating the presence of proteins.
Besides, the addition of Iodine reagent to the starch solution, the color changed to dark blue. On placing a drop of oil on the brown paper, and adding iodine, the water drop disappeared while the oil remained.
It follows that all the reagents identified the organic molecules respectively. Therefore, the hypothesis was successful.
