Question

What is the criterion for DNA fragments movement on agarose gel during gel electrophoresis?

• A. The smaller the fragment size, the farther it moves.
• B. Positively charged fragments move to farther end.
• C. Negatively charged fragments do not move.
• D. The larger the fragment size, the farther it moves.

Answer 1

Answer: (A)

Gel electrophoresis was developed by Tiselius and is based on the principal that charged molecules move to electrode of opposite charge when placed in electric field and the movement depends on the charge and size of the molecule.
Due to the sieve-like texture of the gel, smaller DNA fragments travel faster toward the electrode than the larger fragments.