1. NORTH-WEST UNIVERSITY
BGYM 314
GEL ELECTOPHORESIS
Thage karabo 22300465
Brian Munansangu 22937803
Mohomud Adem 21888205
Phemelo Kampie 23129050
Thabang Mashila 23004622
Frankel Tabiso 23264748

2. Gel electrophoresis
 Gel electrophoresis is a procedure that separates charged molecules
by migration in an electrical field. The rate of migration is
determined by the charge on the molecule and by its size and shape.
Gel is made of agarose or polyacrylamide, a polysaccharide.
 How gel electrophoresis works
 Firstly Deoxyribonucleic acid (DNA) has to be digested with
restriction enzymes since it is usually super coiled. They cut DNA
molecules into segments that range in length from a few hundred to a
few thousand base pairs. After cleaving the DNA, the fragments
generated can be separated from each other for this reason, DNA is
usually cut with restriction enzymes prior to electrophoresis.
Secondly a gel is prepared; The gel is prepared with wells at one end
so that DNA samples can be loaded into the gel.


4.  When nucleic acids are placed at the negative end of an
electrical field, they migrate towards pole with a positive
charge due to their negatively charged phosphate group. Each
fragment’s migration rate is determined by its molecular
weight so that the smaller a fragment is, the faster it moves
through the gel. Migration rate is also a function of gel
density. The presence of the gel meshwork hinders the
progress of the DNA, and small or compact molecules migrate
more rapidly than large molecules. The higher the
concentration of the gel, the more large molecules are
hindered.
 After the gel has been run for sufficient time to separate the
DNA molecules, it can be stained with a compound that binds
to DNA, such as ethidium bromide, and the DNA will then
fluoresce orange under ultraviolet light.
 DNA fragments can be purified from gels and used for a
variety of purposes.

7. Uses of Gel Electrophoresis
 Gel electrophoresis is used to provide genetic
information in a wide range of data fields,Such as
forensics, molecular biology, genetics, microbiology
and biochemistry.
 Human DNA can be analyzed to provide evidence in
criminal cases, to diagnose genetic diseases, and to
solve paternity cases. Samples can be obtained from
any DNA-containing tissue or body fluid, including
cheek cells, blood, skin, hair, and semen.
 Separation of restricted genomic DNA prior to
Southern transfer, or of RNA prior to Northern
transfer.

8. ADVANTAGES
 Provides a clear link between similar results
 Relatively simple to perform
 Can test DNA from any type of evidence
(hair, blood, skin, body fluidetc.)
 Relatively inexpensive

9. DISADVANTAGES
 The disadvantages of gel electrophoresis are:
 The gel can be altered and provide inaccurate results.
 User error can be catastrophic, depending on the
mistake.

10. ETHICAL CONCERNS
 There are very few ethical concerns with gel
electrophoresis, as it is only a process by which you can
obtain DNA evidence, and is usually only used for the
good of society, such as crime fighting, suspect
identification, paternity testing, etc.

11. References
Willy ,J.M & et’al.2008. PRESCOTT’S
MICROBIOLOGY.Singapore: McGraw-Hill
Michael T. M & et’ al. 2012.BROCK BIOLOGY OF
MICROORGANISMS 13TH ed.San Francisco: Pearson
Education,inc.
www.wikipedia.gel eletrophoresis.23 February 2013