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Basics | When and how it is used in our practice
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Basics |
Molecular biological methods are used for analysing cell material on
the molecular level. DNA and RNA are the most relevant molecules in
this analysis, being nucleic acids or so-called “genetic material” and
thus carrying the genetic information of organisms. Polymerase
chain reaction (PCR) is one of the most important methods for the
differentiation and visualization of nucleic acids of various species.
Example: The DNA of the tuberculosis bacterium in cell material of a tuberculosis patient.
Other methods reveal, for example, mutations responsible for hereditary diseases.
With the help of molecular biological methods, scientists can find out
exactly why a cell does what it does. Why does this cell change to a
tumour cell, why are certain bacteriae so dangerous for humans and why
are other bacteriae useful for humans?
All these questions can be analysed with these methods.
The rapid diagnosis of infectious diseases or the determination of
resistances of certain pathogens against antibiotics such as penicillin
are other areas in which molecular biological methods play an important
role.
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In PCR analyses, a certain enzyme – polymerase – is used.
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DNA damage
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This enzyme is present in vital cells, repairing cellular DNA
damage, a property which is made advantage of in the test tube. Certain
short, artificially produced DNA pieces are added to the DNA to be
analysed, thus simulating a faulty DNA strand.
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DNA polymerase at “repair works”
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The following figures show in diagram form how the enzyme travels along the DNA strand, fitting in the missing constituents.
The development of new DNA strands can be demonstrated in an number of ways.
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DNA detection by fluorescence
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In the most recent variant, a pigment bound to repair
constituents is used, which will become fluorescent as soon as it is
separated by the enzyme.
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