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بعض الأجهزه المستخدمة في الوراثة الجزيئية. Explanation of some equipment and operation ways. Eppendorf tubes. deep well plate. Micropipettes. Pipette. electrophoresis equipment. Centrifuge . Techniques in molecular genetics. DNA Extraction .
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بعض الأجهزه المستخدمة في الوراثة الجزيئية Explanation of some equipment and operation ways
Eppendorf tubes deep well plate.
Micropipettes Pipette
electrophoresis equipment Centrifuge
DNA Extraction DNA isolation is a routine procedure to collect DNA for subsequent molecular or forensic analysis. There are three basic and two optional steps in a DNA: • Breaking the cells open, commonly referred to as cell disruption or cell lysis, to expose the DNA within. This is commonly achieved by chemical and physical methods-blending, grinding or sonicating the sample. • Removing membrane lipids by adding a detergent or surfactants. • Removing proteins by adding a protease(optional but almost always done) then separated by ultracentrifuge . • washing the supernatant ( DNA and RNA) by protease, twice and used ultracentrifuge in each time .
Removing RNA by adding an RNase (often done) and used ultracentrifuge. This step repeated twice. • Precipitating the DNA with an alcohol usually ice-cold ethanol or isopropanol. Since DNA is insoluble in these alcohols, it will aggregate together, giving a pellet upon centrifugation.
Refinements of the technique include adding a chelating agent to sequester divalent cations such as Mg2+ and Ca2+, which prevents enzymes like DNase from degrading the DNA. • Cellular and histone proteins bound to the DNA can be removed either by 1- adding a protease or 2- by having precipitated the proteins with sodium or ammonium acetate, or3- extracted them with a phenol-chloroform mixture prior to the DNA-precipitation.
Another method for extraction of nucleic acids from plant tissues