Predict DNA band positions from fragment molecular weight and explain how concentrated gels slow movement through smaller pores and greater resistance using marked questions.
Gel electrophoresis is used to separate DNA fragments of different lengths.
The rate at which the DNA fragments move through the gel depends on several factors including:
- molecular size of the DNA fragment
- shape of the DNA fragment
- concentration of the gel.
Fragments of double-stranded DNA move through the gel at a relative rate ( ) that is inversely proportional to the log of their molecular weight (MW).
The diagram shows the position of a DNA fragment with a MW of 10000, after gel electrophoresis.
Complete the diagram to show the position of a DNA fragment with a MW of 100000.
Use the information in the question.
The fragments move more slowly through a higher concentration of gel. Suggest why the fragments move more slowly through a higher concentration of gel.