Mastering Gel Electrophoresis Techniques in DNA Analysis

Gel electrophoresis is a technique used to separate DNA fragments by size and shape. DNA samples mixed with glycerol and dyes are loaded into a gel. An electric current causes negatively charged DNA to migrate towards the positive electrode. Migration speed depends on DNA size and shape. After electrophoresis, UV light reveals DNA bands stained with ethidium bromide. A DNA ladder helps determine fragment sizes, while control lanes verify recombinant plasmid presence.

What is the purpose of using a viscous liquid in gel electrophoresis?

• To change the color of the gel

• To increase the speed of DNA migration

• To help DNA samples sink into the gel wells

• To make the gel more transparent

Which dye is NOT mentioned as being used in gel electrophoresis?

• Methylene blue

• Bromophenol blue

• Orange G

• Ethidium bromide

Which factor does NOT affect the speed of DNA migration through the gel?

• The electrical current applied

• The color of the dye used

• The shape of the DNA fragment

• The size of the DNA fragment

What happens to DNA fragments when an electrical current is applied?

• They move towards the positive electrode

• They change color

• They move towards the negative electrode

• They remain stationary

Why might plasmids of the same size show multiple bands on a gel?

• They have different sequences

• They are mixed with different buffers

• They are stained with different dyes

• They take on different shapes

What is the role of ethidium bromide in gel electrophoresis?

• To stain DNA for visualization under UV light

• To separate DNA fragments by size

• To speed up the migration of DNA

• To increase the viscosity of the gel

What is the purpose of a DNA ladder in gel electrophoresis?

• To increase the speed of DNA migration

• To determine the sizes of DNA fragments

• To separate DNA fragments by charge

• To change the color of the gel

How do control lanes help in gel electrophoresis?

• They increase the speed of DNA migration

• They confirm the presence of recombinant plasmids

• They provide a reference for DNA fragment sizes

• They change the color of the gel