All Sugars Are Not Monosacharides

All sugars are not monosaccharide's because some sugars like sucrose are made up of a glucose and a fructose, which makes it a disaccharide. Water served as the control for the various tests because it has no nutrients (H2O). In the monosaccharide test the unknown substance turned green proving a positive reaction, this showed us that the presence of sugars was there and there was a reaction with the benedict. The second test was the starch test however this test proved negative since there was no change in colour after adding the iodine.The third test was the Sudan IV lipid test. After adding the Sudan IV the unknown substance turned red proving a positive reaction, and the presence of fats and lipids. The fourth test was the translucence lipid test. The final test was the protein test. When the Biuret was added the unknown substance turned purple proving the presence of proteins .Materials between tests must be clean so the tests can be as accurate as possible. If the materials are not cleaned before a test occurs the outcome of a test may be different, thus altering the results. One error that may have occurred was the use of dirty lab equipment resulting in false results. This can be resolved by making sure all lab tools are clean and dried before use. Another issue that may have occurred was the amount of a substance put in a test tube. For example if instructed to place 3 mL of oil in a test tube putting, but accidently adding more may have changed the results of the tests. Iodine can be used for testing the presence of starch in an object. So if a drop of iodine was placed on a normal piece of white paper it would turn a dark violet colour since paper contains traces of starch. When a protein becomes heated the peptide bonds in the protein become much more energetic causing the bonds to become disrupted. This allowed the biuret test to change from positive to negative.