MCQ for Determination of proteins by Bradford protein assay

Question 1: What is the application of Bradford assay?

Isolation of DNA
INCORRECT. Bradford assay cannot be used to isolate DNA.
Determination of protein concentration
b. CORRECT. Bradford assay is used for determination of protein concentration.
Protein purification
INCORRECT. For protein purification, other methods should be used instead.
Separation of proteins
INCORRECT. For separation of protein, other methods should be used instead.

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Question 2: In Bradford protein assay, what is the dye used in the experiment?

Benedict’s reagent.
INCORRECT. Benedict reagent is for detecting reducing sugars.
Coomassie brilliant blue.
CORRECT. This method relies on the binding of the dye Coomassie brilliant blue to protein.
Methylene blue.
INCORRECT. Methylene blue can stain protein but not as sensitive as Coomassie brilliant blue.
Ethidium bromide.
INCORRECT. ethidium bromide is for staining nucleic acids.

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Question 3: In Bradford protein assay, when Bradford dye reagent binds protein, the dye color will change from?

Blue to Red.
INCORRECT. Please try again.
Red to Blue.
CORRECT. The dye color changes from red to blue after binding protein.
Yellow to Blue.
INCORRECT. Please try again.
Blue to Yellow.
INCORRECT. Please try again.

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Question 4: At which of the below wavelength that absorbance is maximum when Bradford dye reagent binds protein?

At 295nm
INCORRECT. Please try again.
At 330nm
INCORRECT. Please try again.
At 595nm
CORRECT. When Bradford dye binds protein, it has an absorption maximum at 595nm.
At 730nm
INCORRECT. Please try again.

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Question 5: Which of the following statements is false about Bradford assay?

This method relies on the binding of the dye to protein.
INCORRECT. The statement is true. Please try again.
At low pH, the free dye has absorption maxima at 470 and 650 nm.
INCORRECT. The statement is true. Please try again.
The practical advantage of the method is that many proteins dissolve well in the acidic reaction medium.
CORRECT. It is not an advantage, as many proteins will not dissolve properly in the acidic reaction medium. This makes the choice of a standard difficult.
To read the result, the more intense the color, the more protein is present.
INCORRECT. The statement is true. Please try again.

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Finish!