UNIT 3 AOS 1 - Electrophoresis

What is Gel electrophoresis

A laboratory technique used to separate mixtures of DNA, RNA or proteins according to molecular size

How does gel electrophoresis work?

DNA is loaded into an agarose gel

An electrical charge is used to make the DNA travel through the gel

Since DNA is negatively charged, it will move towards the postive terminal

How do distance and size correlate in the bands?

Smaller pieces travel further while larger pieces do not travel far

What does the number of bands tell us?

How many times it was cut

What is the purpose of a DNA standard ladder?

Provides a reference for the size of the molecules that are being separated in the gel. It can also be used as a direct comparison for the samples.

Factors that affect movement of DNA fragments

• Voltage (higher voltage = more distance)

• Gel composition (more dense = less distance)

• Buffer concentration (higher concentration = more distance)

• Time (longer = more distance)

Where is the highest number in a gel electrophoresis apparatus?

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