Effect of Ethidium Bromide on Supercoiling & Electrophoresis

The video tutorial explains DNA topoisomers, focusing on how their shapes affect movement through agarose gel. It discusses the role of ethidium bromide in inducing positive supercoiling and its carcinogenic nature. The tutorial uses graphs to illustrate sedimentation velocity and supercoiling, and describes experiments to determine DNA's original state using ethidium bromide.

What is the primary difference between DNA topoisomers?

• They have different sequences.

• They have different shapes.

• They have different base pairs.

• They have different lengths.

Why does supercoiled DNA travel further in an agarose gel compared to relaxed DNA?

• It has a higher charge.

• It is more compact and experiences less drag.

• It is longer.

• It is heavier.

What is a major safety concern when handling ethidium bromide?

• It is corrosive to metals.

• It is explosive.

• It is highly flammable.

• It is extremely carcinogenic.

How does ethidium bromide affect DNA supercoiling?

• It shortens DNA length.

• It induces negative supercoiling.

• It induces positive supercoiling.

• It breaks DNA strands.

What does sedimentation velocity measure in DNA electrophoresis?

• The length of DNA strands.

• The weight of DNA molecules.

• The charge of DNA molecules.

• The rate at which DNA moves through the gel.

What happens to the sedimentation velocity of DNA as it becomes more positively supercoiled?

• It decreases.

• It remains the same.

• It fluctuates randomly.

• It increases.

In an experiment, what indicates that DNA was initially relaxed when ethidium bromide is added?

• The bands disappear.

• The bands remain stationary.

• The bands move upwards.

• The bands move downwards.

How can you distinguish between negatively and positively supercoiled DNA using ethidium bromide?

• By checking the length of DNA.

• By analyzing the movement of bands in the electropherogram.

• By measuring the weight.

• By observing the color change.

What is the effect of adding more ethidium bromide to negatively supercoiled DNA?

• It becomes more negatively supercoiled.

• It becomes relaxed and then positively supercoiled.

• It breaks into smaller pieces.

• It remains unchanged.

What is the role of ethidium bromide in determining the initial state of DNA?

• It changes the DNA sequence.

• It helps visualize DNA under UV light.

• It shifts the DNA supercoiling state.

• It increases the DNA length.