The migration rate of a macromolecule through a gel matrix during electrophoresis depends on which factors?

The migration rate of a macromolecule through a gel matrix during electrophoresis depends on which factors?

• A. Size
• B. Charge
• C. Shape
• D. All of the above

Answer: (D)

Mobility in gel electrophoresis comes from a balance between the electric driving force and the friction of moving through the gel matrix. The driving force grows with the molecule’s net charge: more charge means a stronger pull toward the opposite electrode, so the molecule tends to migrate faster. At the same time, the gel itself presents a sieving environment: bigger molecules experience more collision with the gel fibers and more drag, slowing their movement. Shape also matters because elongated or irregularly shaped molecules interact with the gel pores differently than compact ones of the same size, altering both their effective friction and how they navigate through the network. Put together, size, charge, and shape all influence how quickly a macromolecule migrates, so all of these factors can determine the migration rate.

Mobility in gel electrophoresis comes from a balance between the electric driving force and the friction of moving through the gel matrix. The driving force grows with the molecule’s net charge: more charge means a stronger pull toward the opposite electrode, so the molecule tends to migrate faster. At the same time, the gel itself presents a sieving environment: bigger molecules experience more collision with the gel fibers and more drag, slowing their movement. Shape also matters because elongated or irregularly shaped molecules interact with the gel pores differently than compact ones of the same size, altering both their effective friction and how they navigate through the network. Put together, size, charge, and shape all influence how quickly a macromolecule migrates, so all of these factors can determine the migration rate.