carbohydrates‚ proteins‚ lipids and nucleic acids. In this lab we will test four foods to see if they contain carbohydrates (sugar and/or starches)‚ proteins and lipids. We will use chemical reagents to test to determine the presence of macromolecules: Benidicts solution for sugar‚ Iodine for starch‚ Biurets reagent for protein‚ and Sudan III for lipids. Hypothesis (1 point) If we test buttermilk biscuits for starches‚ sugars‚ proteins and lipids then it will test positive for all. If we test potato
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to step 4 in Part A on p.18) 3.Leave the filter paper to dry for approximately 5-10 minutes 4.Record observations Results: Table 1: Reactions of sample substances to indicators SAMPLEBenedict’s solution + heatIodine solutionFilter paperBiuret reagent 1.protein solutionPurpleNo changeDried upPurple 2.vegetable oilNo changeNo changePaper remained translucentNo change 3.glucose solutionOrangeNo changeDried upNo change 4.sucrose solutionNo changeNo changeDried upNo change 5.starch solutionNo
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1: Biuret results. Substance Tested Predicted Results Biuret Color & Number of drops added 1: Egg white Contain protien 8 drops‚ purple 2: Pepsin none 8 light purple 3: Sugar none 8 none 4: Distilled water none 8 none Questions A. Which of the test tubes are the positive and negative controls? Test tube 1 and 2 are positive controls while 3 and 4 are negative. B. What conclusions can be made about this experiment? Egg white and pepsin contain proteins. C. How might Biuret reagent be
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part c is the 5 Ml of distilled water. The purpose of washing the test tubes thoroughly is so you don’t mix substances‚ which can cause your results to be inaccurate. Hypotheses: 1. If the test samples contain Protein‚ then in the presence of Biuret the color will turn to yellow‚ green‚ or lavender. 2. If the test samples contain Carbohydrates‚ then in the presence of Benedict’s color will turn to “traffic light colors” which consist or orange‚ red‚ yellow‚ and sometimes green. 3. If
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the casein and whey proteins exist within milk‚ it can be concluded that whipping cream is composed of proteins as it is made with milk. Similarly‚ it was assumed that soy milk would also contain proteins as it is a vegetable protein. When the Biuret reagent was added to the soy milk‚ the bottom of the test tube became a lilac hue while the top and middle remained as the original cloudy‚ off-white coloured liquid. Soybeans are among the best plant-based proteins‚ as unlike plant proteins‚ soy protein
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to make a liquid test. Take another test tube with starch solution to act as a control to compare the difference in color after the completion of the experiment. 2) Label each test tube with a marker for the substance. 3) Add 5 drops of iodine reagent solution to each test tube. 4) Note any color change. Positive
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Identifying Organic Compounds Problem: Based on the color of the indicator‚ which type of organic compound will be found in each type of food? Hypothesis: If Benedict solution is added to honey‚ then it will turn. If Biuret solution is added to egg whites‚ then it will turn. If Benedict solution is added to corn oil‚ then it will turn. If Benedict solution is added to glucose‚ then it will turn. If Benedict solution is added to gelatin‚ then it will turn. If Benedict solution is added to butter
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reduced copper in alkaline solutions. This is called a "Biuret" chromophore. The second is the reduction of Folin-Ciocalteu reagent (phosphomolybdate and phosphotungstate) by tyrosine and tryptophan residues. The reduced Folin-Ciocalteu reagent is blue and therefore is detectable with a spectrophotometer in the range of 750 nm. Using the Folin-Ciocalteu reagent to detect reduced copper makes the assay nearly 100 times more sensitive than the Biuret reaction alone. The BCA Assay: The BCA assay is
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* Test tubes * Solutions : ( A‚B‚C‚D‚E‚F‚ and G) * Reagents: ( Iodine‚ Biuret‚ Benedict‚ Ethanol) * Spatula * Heating plate * A test tube cleaning brush * Tray * Beaker * Distilled water * Pipette ( comes with reagents since they are in bottles) Method/Procedure: Step #1: poor the solution into four different test tubes Step #2: In the first test tube put a few drops of a reagent called "biuret". If the solution turns purple‚ then the solution contains protein
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with the Bluret reagent should come out positive for being a protein. The pepsin in the Bluret reagent should be positive and should be a protein. The test for sugar in the Bluret reagent should be negative and I don’t think it is a protein. The test with the distilled water with the Bluret reagent should be negative and is not a protein. In the second experiment to test for glucose with the Benedict reagent sugar should be positive for glucose. Starch mixed with the Benedict reagent is probably
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