Testing For Biological Molecules Flashcards
How to test for sugars using Benedicts reagent
Add it to the sample and heat it in a water bath that’s set to 75 degrees Celsius.
If the test is positive it will form a coloured precipitate
The higher the concentration of reducing sugar the further the colour change goes.
How to test for starch with iodine.
Add iodine solution the test sample
If starch Is present the sample changes from browny orange to dark blue black
If no starch is present it stays browny orange
How to use test for lipids
Shake the test substance with ethanol until it dissolves
Pour the solution into water
If lipids are present the precipitate will show as a milky emulsion
The more lipids the more notice lie the colour will be.
How to test for proteins
Use a few drops of potassium hydroxide to make the solution alkaline
Add some copper sulfate to the solution
If there is no protein the solution will stay blue
If there is protein is present the solution will turn purple
