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As apples ripen, enzymes convert starch into sugars - Edexcel - GCSE Biology - Question 2 - 2023 - Paper 1
Question 2
As apples ripen, enzymes convert starch into sugars. Devise a method to find the optimum pH of an enzyme that breaks down starch. You may use standard laboratory e... show full transcript
Worked Solution & Example Answer:As apples ripen, enzymes convert starch into sugars - Edexcel - GCSE Biology - Question 2 - 2023 - Paper 1
Step 1
Devise a method to find the optimum pH of an enzyme that breaks down starch.
Answer
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Prepare Solutions: Prepare a starch solution, enzyme solution, and a series of buffer solutions with various pH levels (for example, pH 4 to pH 10).
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Set Up Reaction: In separate test tubes, mix equal volumes of starch solution and enzyme solution with each buffer solution.
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Incubate: Allow each test tube to incubate at a specific temperature (e.g., room temperature) for a set time (e.g., 10 minutes).
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Detect Product Formation: After incubation, add a few drops of iodine solution to each test tube. The iodine will turn blue-black in the presence of starch and remain yellow if the starch has been broken down into sugars.
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Record Results: Note the color change for each pH level. The optimum pH is the one where the least blue-black color remains, indicating the most starch has been converted to sugar.
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Repeat Experiment: For accuracy, repeat the experiment multiple times and calculate the average results.