What Is A Positive Test For Glucose

The purpose of this lab was to test different substances using various procedures to see what biomolecules were present and ultimately find out what restaurant Anna Lyza had eaten at before she died. For the first control test, we used vegetable oil to test for lipids. So, if the solution does not contain lipids, it does not become translucent when placed onto a paper bag square and held up to a light. So, it is a negative result. However, in the presence of lipids, the solution will become translucent when placed onto a paper bag square and held up to a light. Therefore in this case, the result is positive. On the other hand, we used albumin egg to test for proteins in another control test. If the solution does not contain proteins, it will not experience any color change and so it is a negative result. When there are proteins existing in the solution, it will turn bluish/purplish and for this reason it is a positive result. Furthermore in the third control test, we used dextrose to test for simple carbohydrates such as glucose. If the solution does not contain simple carbohydrates, it will not undergo any color change and will remain a blue color. So, it is a negative result in this circumstance. If there are simple carbohydrates present in the solution, the solution will turn reddish and so the result is positive. For the last control test, we used starch solution to test

The iodine test is used to identify glycogen and starch. These polysaccharides combine with iodine to

2. Four unknown samples were included in the lab kit: flax seed meal, potato starch, egg whites, and dried milk. Using the results of the biochemical testing, determine which number corresponds to the correct unknown. (8 points)

7)a) You would do the Benedict’s reagent test for simple sugars and the Lugol’s solution or Iodine test for polysaccharides and starch. To test the lipids you would use the Sudan iV test and Biurets reagent test for protein.

Analysis: In this experiment, every substance tested positive for at least 1 organic compound. Corn oil tested positive for lipids. Honey and oats tested positive for starch. Honey, apple juice, and unknown 1 tested positive for sugar. Egg white, gelatin, and unknown 2 all tested positive for proteins. So, not a single substance didn't test positive for at least 1 organic compound. All the indicators used in this experiment change color when in the presence of a compound; therefore, they chemically react with the compound. No errors were made during this experiment

2.List whether each of the following substances was positive or negative for reducing sugar, as indicated by the Benedict's test. (6 points)

Therefore Iodine can be utilized to detect the presence of starch since the reaction of I2+ I- gives us I3 - . What this means is that any substance that becomes blue/black after iodine has been added to it proves that the substance has starch in it. Interestingly enough, when Iodine is added either to white rice or sweet potatoes, these two foods turn to the blue black color that confirms the presence of starch. However, If I add iodine to a banana, it only turns yellow which confirms that the banana does not contain iodine.

The Benedict test, is a test to determine whether a solution has reducing or non-reducing sugars. If the Benedict's test is negative, that means there is not reducing sugars. Next, the Lugol's test is to determine if there is starch in a substance. If the solution is yellow or orange after a Lugol's test, that means it is negative. If the results of a Lugol's test is purple or black, then it is

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

We then recorded the initial color. We placed each tube in boiling water for one minute and recorded the color results and gave our conclusion. To test for starch using Lugol’s solution, we reused the test tubes and added a squirt of the solution. We recorded the final color and then our conclusion for each content. To test for lipids using paper towels, we placed a drop of solution and we let it stand for one minute. We then recorded our observation, if it was dry or not dry and wrote our conclusion for each sample. To test for proteins using Biuret’s reagent, we added a squirt of stock solution plus a few drops of Biuret’s solution. We wrote the initial color. We then shook the solution and waited for two minutes before recording the results. After the two minutes, we wrote the final color and conclusion for each content. For the unknowns, we wrote the odor and appearance of each content and then tested the benedict’s, starch, lipid, and protein test and wrote our conclusion.

Macromolecules BCM 261 10/13/2014 Caroline Venter 13019865 Introduction Background Many of the molecules that are crucial in living organisms and systems are very large and are usually made up of macromolecules. Macromolecules are organic molecules with a large molecular mass and consist of repeating units called monomers. These repeating monomers are formed via condensation or dehydration reactions (loss of water or other small molecules in order to join two molecules) and usually each have a small molecular mass which contributes to the overall large molecular mass of macromolecules (Jenkins, Kratochvíl, Stepto, & Suter, 2009).

For this experiment, we have to prepare our phosphorylase which extracted from a potato. We prepared by weighed about 250 grams of peeled potato and cut it into cubes. The extracts then blended with 100mL of 0.1M NaF. After filtered the contents into a clean 250mL centrifuge bottle, we centrifuged it for 3 minutes. Then, separated the supernatant into a centrifuge bottle, which is our phosphorylase preparation. The enzyme assay used in this experiment today is the iodine test. As the iodine reacts with starch, it will form a brown, blue or black precipitate due to the iodine ions forcing into a linear arrangement. The endpoint of the enzyme reaction indicates the presence of starch by using the iodine test to determine. The faster the endpoint is reached, the less active the phosphorylase is.

Name ____________________________ I) Introduction All cells contain four major types of macromolecules: carbohydrates, lipids, nucleic acids, and proteins. In today’s lab, we will be studying three of the four-proteins, carbohydrates and lipids. Various chemical tests can be used to detect the presence of each of these molecules. Most of the tests involve a color change visible to the eye. If a color change is observed, the test is considered positive. If the color change is not observed, the test is negative, indicating that a particular molecule is not present. In all the chemical tests we will be performing, we will also be using a control. In most cases, the control will be a sample of

Purpose the purpose of this experiment was to perform test to detect the presence of carbohydrates, proteins, lipids, and nucleic acids. Explain the importance of a positive and a negative control in biochemical test. Use biochemical test to identify an unknown compound.

During the Benedict's test, the contents of tube B did not change, indicating the absence of sugar in that particular substance. However, the contents of tube A did change orange indicating the presence of sugar in that substance. During the Lugol's test, the content of tube A did not change dark purple indicating the absence of starch in that substance However, the content of tube B changed to dark purple