A Sample had reagent solutions used:

Iodine solution (no change),
Biuret solution (pink),
Benedict's solution (yellow)
and Pure water (control, no change).

There was 2 colour changes.

The sample was found to contain trace amounts of glucose and amino acids. Based on the colour changes observed for this sample, provide a Biochemical explanation for these findings.

Demonstrate biochemistry-based principles behind reagent tests (that can result in more than one observable colour change depending on the amount of solute in the sample).

See my response to the first question below.