Effect of DNA Supercoiling on Agarose Electrophoresis

The video tutorial by Kevin Tokoph at Catalyst University explains DNA electrophoresis in agarose gel, focusing on how DNA size and supercoiling affect migration. Using an analogy of crumpled paper, it illustrates how supercoiled DNA migrates faster due to reduced drag. The tutorial also introduces topological isomers and the role of topoisomerases in altering DNA supercoiling.

What determines the distance DNA migrates in an agarose gel?

• The color of the DNA

• The size of the DNA

• The temperature of the gel

• The pH level of the solution

What are topoisomers?

• DNA strands with identical sequences but different supercoiling

• DNA strands with different lengths

• DNA strands with different base pair compositions

• DNA strands with different sequences

How does supercoiling affect DNA migration in agarose gel?

• Supercoiled DNA migrates slower due to increased drag

• Supercoiled DNA migrates faster due to reduced drag

• Supercoiled DNA migrates at the same rate as relaxed DNA

• Supercoiled DNA does not migrate at all

What analogy is used to explain the migration of supercoiled DNA?

• A flat piece of paper and a crumpled ball

• A car and a bicycle

• A fish swimming upstream

• A bird flying against the wind

What is the effect of a high degree of supercoiling on DNA migration?

• It causes the DNA to migrate a shorter distance

• It causes the DNA to change color

• It has no effect on DNA migration

• It causes the DNA to migrate a longer distance

What tool can be used to assess the degree of DNA supercoiling?

• A spectrophotometer

• A microscope

• Ethidium bromide

• A centrifuge

Which of the following describes a relaxed DNA molecule?

• It is highly supercoiled

• It is linear and migrates the furthest

• It has a lot of surface area and migrates slowly

• It is more aerodynamic and migrates quickly