Lab report: Properties of Macromolecules

Macromolecules are those with a significant number of electrons, such as nucleic acid, protein, or synthetic polymer (“”BBC – GCSE Bitesize: Macromolecules.””). Since macromolecules make up the majority of living organisms, they are important building blocks for living things. They play an important role in the survival and reproduction of living things. Any examples of typical macromolecules are as follows.
Carbohydrates are organic compounds present in both living things and foods, and their primary function is to provide short-term energy. Carbohydrates are classified into three types: disaccharides, monosaccharides, and polysaccharides. The monosaccharide or simple sugars are also identified as monomers hence they are absorbed into the body faster than either disaccharides or the polysaccharides. The disaccharides are basically two monomers translating to two sugars. On the other hand, the polysaccharides contain more than two sugars hence they are referred to as complex carbohydrates and they provide long-lasting energy than the previous two. Starch is an example of a polysaccharide.

The lipids just like the starch provide living things with energy but of less quantity in comparison. The lipids can be categorized into those with or without fatty acids. The fatty acids are compounds of hydrocarbons having the carboxyl group (COOH) at their ends (Zhang, Yuanfei, et al. 3890). The fatty acid lipids can as well be classified as waxes, glycerides, and phospholipids, where the glycerides are basically the fats and oils. In addition to that, they can be saturated or unsaturated with the use of hydrogen. The wax as a category of glycerides is hydrophobic thus preventing the gain or loss of water.

The testing for the macromolecules to ascertain their identity involves simple procedures with specific reagents. For example, the test for carbohydrates involves Lugol’s reagent and Benedict’s solution for the complex and simple carbohydrates respectively (“Testing for Lipids, Proteins and Carbohydrates | SEP LESSONS”). The lipids and proteins are tested using Sudan Red test or grease spot test and Buiret test respectively.

Discussion

Many food substances will contain nucleic acids because they are found in many macromolecules that are building blocks for living organisms. The experiment done had results that were meant to identify the ten unknown macromolecules. These results had some similarities with the predicted test results while others deferred with the results. For example, the test with Benedict’s solution was all positive except with albumin and diet soda. This could have been because of contamination of the substances. Secondly, the test with Iodine was as well positive in some cases but different in other cases. For example, it was positive in diet soda among others and negative in grape juice among other. The discrepancy in the results can be because of the different contents in the substrates not included in what was expected.

The Biuret test had cases involving glucose, sucrose, starch and milk t have positive predictions but it was not the same case with such elements as bean, saccharides solution among others. The reason for this might have been because the Biuret test is specific to saccharides. This lead to other substrates not yielding the results as predicted. Last but not the least, the test with the paper had positive results in cases with glucose solution, sucrose solution, starch solution, and milk. The rest had varying results from prediction. The reason for this is also based on the trend of the results as the positive results were only for the saccharides and other compounds had different results. This implies that the paper test responds consistently with saccharides but not with the other substrates.

Works cited

“BBC – GCSE Bitesize: Macromolecules.” Bbc.Co.Uk, 2012, http://www.bbc.co.uk/schools/gcsebitesize/science/add_aqa/bonding/structure_propertiesrev2.shtml.

“Testing For Lipids, Proteins And Carbohydrates | SEP LESSONS.” Seplessons.Org, http://www.seplessons.org/node/362.

Zhang, Yuanfei, et al. “Carboxylic Acids as Traceless Directing Groups for the Rhodium (III)‐Catalyzed Decarboxylative C H Arylation of Thiophenes.” Angewandte Chemie 127.12 (2015): 3888-3892.