BIOMOLECULES AND ENZYMES

Detailed explanation-1: -The biuret reaction is based on the complex formation of cupric ions with proteins. In this reaction, copper sulfate is added to a protein solution in strong alkaline solution. A purplish-violet color is produced, resulting from complex formation between the cupric ions and the peptide bond.

Detailed explanation-2: -The reason behind this colour is the formation of a chelate complex or the copper coordination complex. Cu (II) or cupric ions create a chelate complex of violet colour, using oxygen of water and the unshared electron pairs of peptide nitrogen. Since this complex absorbs light in 540 nm, it appears violet.

Detailed explanation-3: -The biuret test is a chemical assay that detects the presence of proteins in a sample. The test relies on a color change to confirm the presence of proteins. If proteins are found, the sample will turn violet.

Detailed explanation-4: -We used Biuret’s reagent to detect the presence of proteins in solution. The reagent is pale blue when pure, but when mixed with proteins, the resulting reaction produces a pale purple color.

Detailed explanation-5: -Protein in food can be tested using Copper sulphate and caustic soda solution. If protein is present in the food item the colour of the sample changes to violet. As Milk contains protein, it turns violet when reacted with Copper Sulphate and caustic soda solution.