Biological molecules - Biochemical tests Flashcards
What is the test for reducing sugars?
Add benedict’s reagent to the sample.
Heat test tube in a water bath
What is a positive result for a test for reducing/non-reducing sugars?
Colour change from blue to brick red.
What is the test for non-reducing sugars?
Add dilute hydrochloric acid to the sample and heat in a water bath. Neutralise the solution with sodium hydrogencarbonate. Add benedict’s reagent and heat the sample.
Give examples of reducing sugars.
Galactose, glucose, fructose and maltose.
Give an example of a non-reducing sugar.
Sucrose
What is the test for starch?
Add a few drops of iodine in pottassium iodide solution to the sample.
What is a positive result in the test for starch?
Orange/brown to blue/black colour change.
What is the test for lipids?
Add ethanol to the sample, shake to mix, then add to a test tube of water.
What is a positive result of the test for lipids?
A milky emulsion will form, and the solution will appear cloudy.
What is a positive result of the test for lipids?
A milky emulsion will form, and the solution will appear cloudy.
