General Biology I, Fall 2011 Lab Report 3
Name: Luan Nguyen
Lab: Gel Electrophoresis
Purpose of this lab:
In this laboratory investigation, students will analyze hypothetical human DNA using restriction endonucleases and gel electrophoresis to match samples from a crime scene to a suspect.
Your analysis unit will use gel electrophoresis to determine the guilty party. Electrophoresis is a technology in science that allows an individual to separate molecules according to size. The procedure works analogous to a screen, in which larger particles are less likely to move through than small particles. Thus, in electrophoresis, using agarose gel as the “screen”, smaller molecules will move farther than larger particles. When these fragments have a composition that allows them to be seen, the resulting electrophoresis will produce bands of color where fragments have stopped. Ideally, if two samples are placed side by side in the gel, fragments of equal size will move an equal distance from the starting point, allowing the scientist to identify whether or not similar size fragments are in two different samples. For the molecules to move, electrical current “causes” the movement of the molecules. These procedures form the basis of DNA fingerprinting, where electrophoresis separates fragments of DNA. A blood sample from a crime scene can be compared to a blood sample from a suspect. When chemicals called, restriction enzymes, are used to cut up pieces of DNA, both samples will be cut at the same place if the crime scene sample came from our suspect. When these two samples are placed in an electrophoresis device, identical banding patterns should occur, leading us to interpret that the crime scene DNA and the suspect’s DNA are the same
• Agorose Gel
• 250 mL beaker
• Electric box
• Electric contacts + and – charges
• Plastic electrophoresis devices...
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