Question

Which of the following technique(s) can be used to separate proteins according to their molecular weights from a mixture of proteins?

• A. Ion exchange chromatography
• B. Size exclusion chromatography
• C. Sodium dodecylsulfate–polyacrylamide gel electrophoresis (SDS–PAGE)
• D. Sucrose density gradient centrifugation

Hint:

Always link the separation principle to the property: charge (ion exchange), size/shape (size exclusion), molecular weight (SDS–PAGE), or density/size (gradient centrifugation).

Answer 1

The Correct Option is B, C, D

(A) Ion exchange chromatography separates proteins based on their charge, not molecular weight. ❌
(B) Size exclusion chromatography separates proteins based on size/shape, effectively correlating with molecular weight. ✔️
(C) SDS–PAGE separates denatured proteins by molecular weight after SDS treatment equalizes charge-to-mass ratio. ✔️
(D) Sucrose density gradient centrifugation separates macromolecules based on sedimentation rate, which depends largely on size and mass. ✔️
Hence, correct techniques are (B), (C), and (D).