Predict Reactions & Macromolecules for Benedict's, Iodine & Bauret Tests

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In summary, the conversation discusses the use of various tests in biology lab for identifying the presence of different macromolecules in food. These include benedict's test for reducing sugar, iodine (I2KI) for starch, and the Biuret test for proteins. The expected color changes for positive and negative reactions are also mentioned. The individual also questions how to determine a positive result for benedict's test and whether knowledge of the food's components is necessary.
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Genericcoder
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So I am asked this question in biology lab we aren't provided by any information to how to solve it,but we are asked to research on the internet in order to solve it.

Predict the reactions you would expect to see for the following foods if they were tested using benedict's test, iodine (I2KI) and the Bauret test. include the colour you would expect to see whether would indicate a positive or negative reaction. If you expect the reaction to be positive, state which macromolecule you would expect to be present in the greatest abudance.


So I read about Benedict's test which tells us if there is reducing sugar that is available in that food or not which means a positive test with benedict's test would have free aldehyde or ketone groups as macromolecule and colour changes for negative test would be blue and red for positive.

For Biuret test its pretty easy it would be positive for any food that contains proteins,so I know this about Biuret test.

I want to know though how can I know if a result is positive or not for benedict's test do I have to know the components of the food itself ?
 
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  • #2
didnt you kind of answered your question in the previous sentence
 

1. What is the purpose of the Benedict's test?

The Benedict's test is used to detect the presence of reducing sugars in a substance. It involves the reaction of reducing sugars with copper (II) ions, which results in a color change from blue to green, yellow, orange, or red depending on the concentration of reducing sugars present.

2. How is the iodine test used to identify the presence of a polysaccharide?

The iodine test is used to test for the presence of starch, a type of polysaccharide. It involves adding iodine solution to a sample and observing if a blue-black color appears, which indicates the presence of starch.

3. Can the Bauret test be used to identify the presence of proteins in a sample?

Yes, the Bauret test can be used to detect the presence of proteins in a sample. It involves adding a solution of copper (II) sulfate and sodium hydroxide to the sample, which results in a color change from blue to violet or purple in the presence of proteins.

4. Are there any limitations to using the Benedict's test for detecting reducing sugars?

Yes, there are limitations to using the Benedict's test. Some substances, such as non-reducing sugars and other compounds, can also give a positive result even though they are not reducing sugars. Additionally, if the concentration of reducing sugars is too low, the color change may not be easily visible.

5. How do these tests help in the identification of macromolecules?

These tests are specific for certain types of macromolecules, such as reducing sugars, starch, and proteins. By performing these tests on a sample, scientists can determine the presence or absence of these macromolecules, which can provide valuable information about the composition of the sample.

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