Question

A student heats a test tube containing a large amount of protein and biuret reagent. She notices a color change from violet to blue. Explain why heating causes a color change

Answer 1

Step-by-step explanation:

Proteins are formed from amino acids that are held together by peptides bonds. We have excess of protein present with Biuret reagent which is a combination of sodium hydroxide(NaOH) and copper sulfate(CuSO4)

The normal color of biuret reagent is blue but when we have protein present in biuret reagent its color will be Violet and when we heat this the protein present in it will gain molecular energy disrupting the peptides bonds present as a result the color changes now to blue which is the original color of the biuret solution this happened because biuret test was used to detect proteins or peptide bond specifically but now they are disrupted hence the color change.