1 Biological Molecules: Biuret

Question 1

What is the Biuret test?

Answer 1

• simple biochemical reaction to detect the presence of amino acids/ proteins

Question 2

How do you carry out the Biuret test?

Answer 2

• add excess Biuret Reagent to sample
• shake and leave at room temperature

Question 3

What is the colour of the Biurets reagent

Answer 3

• pale blue

Question 4

What are the hazards and precautions of the Biuret test?

Answer 4

• biurets reagent is an irritant = wear goggles, wash hands with water on contact with skin

Question 5

Describe a positive result for the Biuret test

Answer 5

• biuret solution turns purple , indicating a protein being present

Question 6

Describe a negative result for the Biure test

Answer 6

• biuret solution stays light blue, indicating no proteins are present

Question 7

Describe the quantitative measurement for the Biuret test

Answer 7

• more amino acids are present, the stronger the purple colour = qualitative
  -chromatography can be used to identify amino acids in a mixture, separating them by mass