BIOLOGY
PROTEINS
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Question
[CLICK ON ANY CHOICE TO KNOW THE RIGHT ANSWER]
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From blue to brown
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From blue to green
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From blue to red
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From blue to purple
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Detailed explanation-1: -This compound appears violet since it absorbs light at 540 nm. Its colour shifts from blue to violet when protein is present.
Detailed explanation-2: -Biuret solution is made by mixing copper sulfate with sodium hydroxide. Copper sulfate gives a typical blue color to this solution, which is turned to purple after reacting with the proteins.
Detailed explanation-3: -Sodium hydroxide provide the alkaline medium and potassium sodium tartrate is added to chelate and thus stabilize the cupric ions in the solution or to maintain their solubility in alkaline solution. The copper (II) present in the reaction binds itself to the nitrogen atoms that are present in the protein peptides.
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: -Proteins are detected using Biuret reagent . This turns a mauve or purple colour when mixed with protein.