MCAT Question of the Day
    •

    Q:

    		 SDS is a negatively charged detergent used to disrupt noncovalent bonds between amino acids in a protein. One molecule of SDS binds on average to two residues of a protein. The protein segments are then separated by gel electrophoresis (an electric field is applied to the gel containing the protein segments) on the basis of molecular weight. The rate of movement of the protein through the gel is inversely proportional to the log of the molecular weight.

    Which protein segments do you expect to be at the bottom of the gel after electrophoresis (furthest from the point of origin)?

    		 

    A

    		 The most negatively charged segments

    B

    		 The heaviest segments

    C

    		 The lightest segments

    D

    		 The most positively charged segments



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