Protein + Lipids Test Flashcards
What test is used to test for proteins?
The biuret test
What test is used to test for lipids?
The emulsion test
How does the biuret test detect proteins?
By detecting the presence of peptide bonds
How do you do the biuret test?
4
Put the sample being tested in a clean test tube
Add biuret A (sodium hydroxide) to the test tube
Add a few drops of biuret B (copper (II) sulphate)
Gently mix the solution
What is biuret A?
sodium hydroxide
What is biuret B?
copper (II) sulphate
The biuret test
How will you know if protein is present?
The colour of the reagent will change from blue to purple (if present)
(If not present it will stay blue)
How do you do the emulsion test?
5
Put the sample being tested in a clean test tube
Add ethanal to the test tube
Thoroughly mix the solution to dissolve any lipid
Add water to the test tube
Mix gently
The emulsion test
How will you know if lipid is present?
It will become a cloudy white substance
The emulsion test
Why does it become a cloudy white substance?
The cloudy white substance appears as lipids are not soluble in water so they come out of the solution and form an emulsion
