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Questions and Answers
Which type of sugars does the Benedict's test detect?
What color change indicates the presence of starch in the iodine test?
In the buret test for proteins, what color change indicates the presence of proteins?
What is the purpose of adding three drops of the Sudan 3 stain solution in the test for lipids?
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What is the first step in preparing a food sample for the different food tests mentioned in the text?
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Which test is a simpler test for starch?
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What does the Sudan 3 test specifically detect?
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Study Notes
- The video covers the different food tests required for GCSE biology practicals, including the Benedict's test for sugars, iodine test for starch, buret test for proteins, and Sudan 3 test for lipids.
- For all the tests, the food sample needs to be prepared by crushing it with a pestle and mortar, adding it to a beaker with distilled water, stirring it with a glass rod, and filtering the solution using a funnel and filter paper.
- Sugars are small units that make up carbohydrates and come in two types, reducing sugars and non-reducing sugars, with the Benedict's test only detecting reducing sugars.
- The iodine test is a simpler test for starch and involves adding a few drops of iodine solution to a food sample and observing the color change to blue-black if starch is present.
- The buret test for proteins requires adding a larger amount of the food sample to a test tube, followed by the addition of burette solution, and the observation of a color change from blue to pink or purple if protein is present.
- For the Sudan 3 test for lipids, no filtering of the food sample is required. Three drops of the stain solution are added to the test tube, and a bright red layer appears at the top if lipid is present.
- The emulsion test for lipids in the EdExcel course involves adding ethanol and distilled water to the food sample, with a cloudy white color indicating the presence of lipid.
- All tests require careful preparation and observation to determine the presence of the respective food components.
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Description
Test your knowledge on the different food tests required for GCSE biology practicals, including the Benedict's test for sugars, iodine test for starch, buret test for proteins, and Sudan 3 test for lipids. Understand the preparation of food samples and the observations needed to determine the presence of specific food components.
