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UPDATED TO 2023-2025 SYLLABUS
CAIE IGCSE
BIOLOGY
SUMMARIZED NOTES ON THE ALTERNATIVE TO PRACTICAL SYLLABUS
Prepared for Khaula Kamran for personal use only.
CAIE IGCSE BIOLOGY
disappearing.
1. Food Tests
Starch: Add a few drops of iodine, +ve result = blue-black
colour
Reducing Sugars: Add Benedict’s reagent, and then the
mixture is heated in a water bath for 2 to 3 minutes.
+ve result (increasing concentration of sugar) = blue →
brick red
-ve result = remains blue
Proteins: Add few drops of Biuret reagent, +ve result =
purple/lilac color, -ve result = remains blue
Fats: For the emulsion test, ethanol is added to the
mixture and poured into a test tube with an equal amount
of distilled water, +ve result = milky-white emulsion.
Vitamin C: Add 1 cm3 of DCPIP solution and a small
amount of food sample (as a solution) to a test tube. A
positive test will show the blue colour of the dye
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CAIE IGCSE
Biology
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