What macromolecule does it test for, what is the positive test color, what is the negative test color
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The test is typically for carbohydrates, specifically starch. Show more…
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5. Match the macromolecule to the chemical used to test for it and then to the color that the chemical would change for a positive test. (8 points) Macromolecule sugar protein lipid starch Reagent Options Biuret Reagent Sudan III iodine Benedict's solution Color Change Options green, orange, or red color blue-black color red or orange color blue-violet color 6. How are the reagents useful in determining which macromolecules are present? (2 points) 7. A very thin slice of a peanut is removed and treated with a Sudan III stain. Then a drop of Biuret reagent is added to the peanut slice. Under a microscope, you observe patches of red (orange) and blue-violet. What conclusions can you draw from these results? (4 points) 8. A cracker is crushed in water will test positive with iodine but negative with Benedict's solution. A cracker crushed in water has amylase added to it. After a few minutes, it tests negative for iodine and positive with Benedict's. Explain. (5 points)
Madhur L.
Benedict's test, Lugol's iodine test, Biuret test, and the Sudan III test were conducted on an unknown sample to determine which macromolecule(s) it contains. The test results are shown below: 1. Benedict's 2. Lugol's 3. Biuret 4. Sudan III For each of the following, circle whether the macromolecule was present or not in the unknown and explain which test result allowed you to arrive at your answer. a. Protein - present / not present Test used to arrive at answer: Explanation: b. Lipids - present / not present Test used to arrive at answer: Explanation: c. Monosaccharides - present / not present Test used to arrive at answer: Explanation: d. Polysaccharides - present / not present Test used to arrive at answer: Explanation:
1) What does a positive reaction to Benedict's solution indicate about the solution you are testing? What change do you expect to see if a solution has a positive reaction to Benedict's solution? 2) What do you expect to see in a positive reaction to Biuret solution? What kind of molecule is present if there is a positive reaction? Specifically, what part of the molecular structure reacts with the Biuret solution? 3) Using the brown paper test, how would you tell if a solution contains lipid? 4) Differentiate between a positive and negative Sudan IV test. Is positive? 5) Which of the following materials would you expect to give a positive result when tested with Lugol's iodine? Explain why. a. Potato b. Glucose c. Starch d. Egg albumin
Jenny W.
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