Macromolecules
Test of Biological Molecules
Tamari Manyengavana
5XVGXTJ96
Laboratory Report
SCPB111
Principles of Biology
Faculty of Applied Sciences
Pearson Institute of Higher Education
14 March 2018
Abstract
Biological molecules are part of Introduction
Biological molecules are formerly known as macromolecules. Macromolecules are large molecules that are formed from smaller molecules called monomers (Ellisman, 2014). They are formed by dehydration reactions, in which a water molecule is removed during the formation of bonds (Wayne Huang, 2015). Biological molecules are organic, indicating that they contain carbon and hydrogen atoms (Gair, 2013). The four classes of biological molecules are carbohydrates, proteins, nucleic acids and …show more content…
During digestion, the stomach breaks down proteins into amino acids, which are then reproduced to help with maintain blood, bone, organ and organ system (Roberts, 2017). The aim of the experiment is to determine the presence of protein, lipids and carbohydrates in the food samples that will be tested. Methodology
Testing of sugar
10 test tubes were used and labelled. 9 of the test tubes were filled with 5ml of food sample.10 drops of Benedict’s solution were added to each of the test tubes, using a dropper. The test tubes were placed in a hot water bath with a temperature of 50 degrees Celsius for five minutes. Colour change within the test tubes were observed and recorded.
Starch test
10 test tubes were used and labelled. 9 of the test tubes were filled with 5ml of food sample.3 drops of Lugol’s iodine solution were added to each of the test tubes. The test tubes were mixed thoroughly. Test tube 1 was placed under a flame for observation. Colour change within the test tubes were recorded.
Protein test
10 test tubes were used and lab-elled. 9 of the test tubes were filled with 5ml of food sample. 3 drops of Biuret reagent were added to each of the test tubes. The test tubes were gently shaken to mix the solution. Observation of colour change was …show more content…
Iodine is insoluble in water, for it to become soluble in water, potassium iodide is added, forming triiodide (MEL Science, 2015). When reacted with starch attach to structures within a starch molecule, leading to a blue-black colour (Ophardt, 2003). Starch is a carbohydrate, which contains two types of polysaccharides that are connected in two different ways, linear amylose and branched amylopectin (Goedecke, 2016). When iodine reacts with amylose, the iodine ‘gets stuck’ in the starch coils, forcing the ion/iodine to become linear as well as changing the electron arrangement. The new electron arrangement alters the molecule’s light absorbance, resulting in colour change. Whereas with amylopectin, when it reacts with iodine, it forms a pale purple colour, as the structure has a small area for binding, resulting in less iodine being absorbed (Becker,
Tamari Manyengavana
5XVGXTJ96
Laboratory Report
SCPB111
Principles of Biology
Faculty of Applied Sciences
Pearson Institute of Higher Education
14 March 2018
Abstract
Biological molecules are part of Introduction
Biological molecules are formerly known as macromolecules. Macromolecules are large molecules that are formed from smaller molecules called monomers (Ellisman, 2014). They are formed by dehydration reactions, in which a water molecule is removed during the formation of bonds (Wayne Huang, 2015). Biological molecules are organic, indicating that they contain carbon and hydrogen atoms (Gair, 2013). The four classes of biological molecules are carbohydrates, proteins, nucleic acids and …show more content…
During digestion, the stomach breaks down proteins into amino acids, which are then reproduced to help with maintain blood, bone, organ and organ system (Roberts, 2017). The aim of the experiment is to determine the presence of protein, lipids and carbohydrates in the food samples that will be tested. Methodology
Testing of sugar
10 test tubes were used and labelled. 9 of the test tubes were filled with 5ml of food sample.10 drops of Benedict’s solution were added to each of the test tubes, using a dropper. The test tubes were placed in a hot water bath with a temperature of 50 degrees Celsius for five minutes. Colour change within the test tubes were observed and recorded.
Starch test
10 test tubes were used and labelled. 9 of the test tubes were filled with 5ml of food sample.3 drops of Lugol’s iodine solution were added to each of the test tubes. The test tubes were mixed thoroughly. Test tube 1 was placed under a flame for observation. Colour change within the test tubes were recorded.
Protein test
10 test tubes were used and lab-elled. 9 of the test tubes were filled with 5ml of food sample. 3 drops of Biuret reagent were added to each of the test tubes. The test tubes were gently shaken to mix the solution. Observation of colour change was …show more content…
Iodine is insoluble in water, for it to become soluble in water, potassium iodide is added, forming triiodide (MEL Science, 2015). When reacted with starch attach to structures within a starch molecule, leading to a blue-black colour (Ophardt, 2003). Starch is a carbohydrate, which contains two types of polysaccharides that are connected in two different ways, linear amylose and branched amylopectin (Goedecke, 2016). When iodine reacts with amylose, the iodine ‘gets stuck’ in the starch coils, forcing the ion/iodine to become linear as well as changing the electron arrangement. The new electron arrangement alters the molecule’s light absorbance, resulting in colour change. Whereas with amylopectin, when it reacts with iodine, it forms a pale purple colour, as the structure has a small area for binding, resulting in less iodine being absorbed (Becker,