Chemical Aspects of Life and Spit Lab Formal Report
The objective of the Reducing Sugar Test was to test if the substance has a reducing sugar in it by adding Benedict’s solution and heating it, there would be a color change if a reducing sugar is present, or it will remain blue (no reducing sugar). The objective of the Starch test was to test for starch in substances by using Iodine. The iodine will cause a substance to turn to a dark blue color if it is positive for starch. The objective for the Grease Spot Test was to test if the substance had a lipid. A positive reaction would make a translucent grease mark on a brown paper bag. The objective for the Dye test was to test for lipids. When mixed with water and the tested substance, a positive result will occur in it being separated from the water. The objective of the Protein Test was to test for proteins present in a substance using the Biuret Solution. The substance should produce a violet color within 10 drops of Biuret. The objectives of the Spit Lab were to test for starch, a reducing sugar, and effect of amylase on a cracker that is positive for starch and negative for a reducing sugar. Iodine would test if starch was present if the cracker solution changes to a dark black/blue color. Benedict’s Solution mixed with the cracker and heated would test for a reducing sugar (if reducing sugar, it will turn from a green to an orange to a dark brownish color). The amylase was tested on a Triscuit cracker by heating it in Benedict’s Solution, the amount would make it either a green, or orange, and the most amounts would make it brown as mine and my partner’s results. 1. Introduction
The chemical aspects lab was done to detect and identify the presence of reducing sugars, starches, lipids, and proteins in various substances. A reducing sugar is a monosaccharide or disaccharide that has the ability of giving electrons to other molecules and acts as reducing agent. A reducing agent has an aldehyde or ketone group in it that can reduce the ions of some metals, such as sodium citrate, copper sulfate, sodium bicarbonate (Benedict’s solution). In order to be a reducing sugar, the sugar must have a beta-beta bond, which is the bond that can be broken by heat. If they have an alpha-beta bond, like sucrose, then the test material does not have reducing sugars present, it will remain blue. If there are reducing sugars present in the substance, the color will change from a green to orange to dark brown state. Starch is a carbohydrate that is found in potatoes and other grains. It is made of a large number of units of glucose. When starch is consumed, the body's enzymes break it down into glucose, a monosaccharide. Starch can be identified in a test material by adding drops of iodine to it. The iodine should go into the polysaccharide chain, so the color changes to a black color, or precipitate will form. A lipid is a hydrophobic polymer made of two monomers. Since they are hydrophobic it differentiates lipids into a separate group of polymers. The monomers that make up lipids are glycerol and three fatty acids. Lipids store energy and are in hormones. There are two ways to be able to detect a lipid in a test material, a grease spot test or a dye test. The grease spot test is used to test for only lipids that are highly concentrated. Lipids are known to be translucent when on paper. So you add a drop of the substance onto a brown sheet of paper and add a drop of water next to it then let them evaporate. After observing the drops through light by holding it up and trying to look through the paper, if it is translucent, it is a lipid. A more accurate test for lipids is the dye test. If water is combined with Sudan III (Sudan IV was replaced by this), and mixed with the test material, the test material can be considered a lipid if the solution forms a pink color. This is because Sudan III (Sudan IV was replaced by this) is only soluble in lipids. The lipid will be...
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