This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Biochemistry
True regarding electrophoresis are all except 
Select and explain. 
A. Isoelectric focusing use ampholytes & pI, B. Adversely affect structure & function, C. Depends on size not on shape, D. Commonest method of purifying protein
C: Depends on size not on shape
Answer: C: Depends on size not on shape 
Explanation: Electrophoresis depends on size as well as on shape
Electrophoresis is the process that uses an electric field to drive the movement of charged particles. Electrophoresis depends on the net charge of the particle, molecular weight, pH of the medium, the strength of the electric field and temperature.

About other options

Ampholyte is used in isoelectric focusing to create a pH gradient across the supporting media. Molecules stop migrating as soon as they reach their respective isoelectric point (pI).



Electrophoresis can adversely affect the structure and function of proteins.
Electrophoresis is the most common method for protein separation.
"Electrophoresis is the most common method of protein separation in the clinical laboratory". 
"PAGE and SDS-PAGE are extensively used for characterization and purification of tissue proteins, enzyme, receptors, and surface antigens".

Electrophoresis uses an electric field