DNA ladder

Definition

A DNA ladder is a molecular weight marker used in gel electrophoresis to estimate the size of DNA fragments. It consists of DNA fragments of known lengths.

5 Must Know Facts For Your Next Test

1. DNA ladders are essential for determining the size of unknown DNA fragments during gel electrophoresis.
2. They typically contain a range of fragment sizes, often from 100 base pairs to several kilobases.
3. The bands created by a DNA ladder can be compared to experimental samples to estimate their molecular weights.
4. DNA ladders are commercially available and can be customized for specific applications in molecular biology.
5. They are often stained with ethidium bromide or other DNA-binding dyes for visualization under UV light.

Review Questions

• What is the primary purpose of using a DNA ladder in gel electrophoresis?
• How are the sizes of the fragments in a DNA ladder typically measured?
• What staining methods are commonly used to visualize DNA ladders?

Related terms

Gel Electrophoresis:

A technique used to separate DNA, RNA, or proteins based on their size and charge.

Ethidium Bromide:

A fluorescent dye that binds to nucleic acids and is commonly used for staining in gel electrophoresis.

Molecular Weight Marker: Another term for a DNA ladder; used as a reference to determine the size of biomolecules during electrophoresis.