Identifying Macromolecules

3065 Words13 Pages
Using Chemical Reagents and Indicators to Determine the Presence of Macromolecules Nutrients in Unknown Solutions Abstract: To use chemical reagents to test for simple sugars and starch, proteins, and fats in the multiple procedure lab. Important equipment that was involved in this experiment included the chemical reagents such as Benedict’s reagent and Lugol’s solution for carbohydrates, Sudan IV indicator for lipids and Biuret reagent for proteins because these reagents determined the colour change for each solution in order to identify the macromolecule. With the use of Benedict’s reagent, solutions that were positive for the presence of monosaccharaides and disaccharides in carbohydrates turn the colour orange they included: fructose, glucose, lactose, and Unknown A. For lugol’s solution, the starch turned the colour black to prove that it was a positive reaction for the presence of polysaccharides in carbohydrates. Sudan IV indicator tested vegetable oil as a positive result for lipids by turning the colour red. For the unglazed paper vegetable oil also tested positive by turning the paper translucent. Lastly Biuret reagent, solutions such as egg whites and skim milk tested positive for the presence of proteins and peptide bonds by turning the colour purple. As a result, for the unknown A solution resulted in being…show more content…
The carbohydrates test had sucrose, fructose, glucose, starch, and lactose, the proteins solutions included agrose, skim milk, and egg white, and the lipids solutions were whipping cream and vegetable oil. These solutions are all examples of manipulated variables that are always changed by the investigator. The dependent variable was the change of colour for each reagent. For every chemical reagent Sudan IV, biuret reagent, Benedict’s reagent and lugol’s there was a desired colour in order to identify the
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