Biochemical Tests for molecules

HideShow resource information
  • Created by: CCOSTER
  • Created on: 20-03-14 13:07

Bichemical Tests for Molecules

The Biuret Test (Proteins)

  • Add a few drops of sodium hydroxide to make the solution alkaline.
  • Then add some copper sulphate solution.
  • If protein is present it will turn from blue to purple. 

The Benedicts test (Sugars)

Reducing Sugars- 

Include all monasaccharides and some disaccharides. 

  • Add benedicts reagant (blue) to sample.
  • Heat it (Do not let it boil) 
  • If test is positive, it will form a cloudy precipitate.
  • The precipitate goes from green-yellow-brick red. 
  • The higher the concentration is the further the colour changes. 
  • Alternatively, the solution can be filtered and the precipitate weighed. 

Non - Reducing Sugars- 

This is carried out after completing the test for reducing sugars. 

  • Break down the sugar into monosaccharides by boiling with dilute hydrochloric acid. 
  • Then add


No comments have yet been made

Similar Biology resources:

See all Biology resources »See all Biological molecules resources »