experiment questions food tests. for what is the biuret test (copper sulphate and sodium hydroxide...
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![Page 1: Experiment Questions Food Tests. For what is the Biuret test (copper sulphate and sodium hydroxide solutions) used in the biology laboratory? Test for](https://reader036.vdocument.in/reader036/viewer/2022062716/56649dce5503460f94ac16a0/html5/thumbnails/1.jpg)
Experiment Questions
Food Tests
![Page 2: Experiment Questions Food Tests. For what is the Biuret test (copper sulphate and sodium hydroxide solutions) used in the biology laboratory? Test for](https://reader036.vdocument.in/reader036/viewer/2022062716/56649dce5503460f94ac16a0/html5/thumbnails/2.jpg)
Food Tests
For what is the Biuret test (copper sulphate and sodium hydroxide solutions) used in the
biology laboratory?
Test for protein
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Food Tests
For what is the Benedict’s (or Fehling’s) test used in the biology laboratory?
Test for reducing sugar
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Food Tests
For what purpose did you use brown paper or Sudan III in food testing?
To test for Fat / Lipid / Oil
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Food Tests
What reagent or chemicals did you use to test for protein?
Biuret OR NaOH and CuSO4
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Food Tests
Is heat necessary in the test that you carried out to test for protein?
No
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Food Tests
What colour change indicates the presence of protein?
From blue to purple / violet
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Food Tests
Name the test or name the chemical used to test a solution for the presence of glucose
(reducing sugar).
Clinistix / Benedicts / Fehling’s / Copper
sulphate
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Food Tests
What colour change indicates a positive result for the presence of glucose?
(Clinistix) Orange to Blue or (others) Blue to Red
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Food Tests
Is heat necessary to test a solution for the presence of reducing sugar?
Yes
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Food Tests
For which purpose did you use Biuret solution or alkaline copper sulphate in food testing?
To test for (soluble) protein
![Page 12: Experiment Questions Food Tests. For what is the Biuret test (copper sulphate and sodium hydroxide solutions) used in the biology laboratory? Test for](https://reader036.vdocument.in/reader036/viewer/2022062716/56649dce5503460f94ac16a0/html5/thumbnails/12.jpg)
Food Tests
State a use for the Biuret test in the biology laboratory.
To detect presence of protein
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Food Tests
What is the initial colour of the reagent or chemicals used to test for protein?
Blue
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Food Tests
Was there a colour change in the control experiment when testing for protein?
No
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Food Tests
Name the test or give the chemicals used to test a sports drink for the presence of protein.
Biuret Test / Sodium Hydroxide & Copper sulphate
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Food Tests
If protein is present in a drink, what colour change would you expect to see? In your
answer give the initial and final colour of the test solution.
Blue to violet /purple / lilac
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Food Tests
Is heat necessary for the test for protein?
No
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Food Tests
For what purpose did you use Fehling’s solution or Benedict’s solution in the course of your
practical activities?
To check for Glucose / reducing sugar
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Food Tests
For which purpose did you use Brown paper or Sudan III in food testing?
To test for fat (or lipid or oil)
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Food Tests—Reducing sugar
(i) Name the reagent(s) used.(ii) State the initial colour of the reagent.
(i) Benedict’s/ Fehlings I and II, (ii) Blue
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Food Tests—Reducing sugar
State whether the test requires heat.
Yes
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Food Tests—Reducing sugar
What colour indicates a positive result?
Brick-red/orange
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Food Tests—Protein
(i) Name the reagent(s) used.(ii) State the initial colour of the reagent.
(i) Biuret solution / CuSO4 + NaOH
(ii) Blue/ light blue
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Food Tests—Protein
State whether the test requires heat.
No
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Food Tests—Protein
What colour indicates a positive result?
Purple / violet
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Food Tests
(i) Name a test to show the presence of a reducing sugar (e.g. glucose).
(ii) Describe how you would carry out this test.
(i) Benedict’s/ Fehling’s (ii) Dissolve sample in water or put in test
tube / add reagent / heat / don’t boil / observe change or state result (brick-red-
orange precipitate)
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Food Tests
(i) Name a test for protein.(ii) Describe how you would carry out this test.
(i) Biuret test or named chemicals (ii) Add biuret reagent (or sodium hydroxide
and copper sulfate) / to sample / heat or shake / observe or record colour change
(purple-violet)
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Food Tests
What chemical did you use to test the food for starch?
Iodine solution
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Food Tests
Was heat necessary to test a food for starch?
No
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Food Tests
After testing with iodine how did you know that starch was present in a sample of food?
Blue/Black colour
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Food Tests
What control did you use when testing a food for starch?
Water instead of starch
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Food Tests
What chemical did you use to test the food for protein?
Biuret (solution) or NaOH & CuSO4
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Food Tests
What was the initial colour of the protein-testing solution before you put it on the food?
Blue
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Food Tests
Was heat necessary to test a food for protein?
No
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Food Tests
What colour indicated that protein was present in the food?
Purple / Violet / Pink