Question

How does gel electrophoresis allow scientists to separate DNA samples based on their size? (Your answer must include the terms positive charge and negative charge!)

Answer 1

Gel electrophoresis and DNA

DNA is negatively charged, therefore, when an electric current is applied to the gel, DNA will migrate towards the positively charged electrode. Shorter strands of DNA move more quickly through the gel than longer strands resulting in the fragments being arranged in order of size.