Electrophoresis Flashcards
Gel electrophoresis uses what to separate what, according to what?
Gel electrophoresis uses an ELECTRIC FIELD to SEPARATE NEGATIVELY CHARGED DNA FRAGMENTS according to SIZE.
Small fragments will travel further in the gel.
Types of gels and what are they used for
Agarose gel; used for larger molecules like dna
Polyacrylmaide gel: used for smaller molecules like proteins
Gel electrophoresis definition
Gel electrophoresis is a procedure used to separate biological molecules by size. The separation of these molecules is achieved by placing them in a gel with small pores and creating an electric field across the gel. The molecules will move faster or slower based on their size and electric charge.
Why does gel electrophoresis work
The process of gel electrophoresis works because negatively charged molecules move away from the negative pole of the electric current and smaller molecules will move faster than larger molecules. Thus, a size separation is achieved within the pool of molecules running through the gel. The gel works in a similar manner to a sieve separating particles by size. The electrophoresis works to move the particles, using their inherent electric charge, through the sieve.
Process of distinguishing between different segments of dna
When researchers are trying to distinguish between different segments of DNA, for example, the process is simple. The samples are loaded into channels at the start of the gel. Each DNA molecule has the same charge (-1), because DNA is formed by the same 4 nucleotides and always carries a slightly negative charge regardless of its size. Therefore, each DNA molecule will have the same force pulling it through the gel.
How does size affect process through the gel
However, the size of each molecule hinders its progress through the gel. Large molecules hit parts of the gel matrix, and are slowed down. Small DNA molecules can slip between the various components of the gel matrix, and quickly make their way to the other side of the gel. After a certain amount of time, the dyed DNA molecules can be seen aggregating in different areas of the gel, based on how far they moved during gel electrophoresis. This allows researchers to identify the segments, and compare the DNA of different organisms.
What is gel electrophoresis used for?
The purpose of gel electrophoresis is to visualize, identify and distinguish molecules that have been processed by a previous method such as PCR, enzymatic digestion or an experimental condition. Often, mixtures of nucleic acids or proteins that are collected from a previous experiment/method are run through gel electrophoresis to determine the identity or differentiate between molecules
