In this activity, lysing the cell wall of a piece of fruit is accomplished by quickly blending or smashing the fruit. Salt is added to the filtered fruit solution to coalesce (combine) the DNA strands that have been freed from the nucleus. Detergent is added to the mixture to break apart and emulsify the lipids and proteins that make up the cell and nuclear membranes. Sodium dodecyl sulfate is an emulsifier used in detergents. Finally, the DNA-destroying enzyme DNase is disabled by adding ethylenediaminetetracetic acid (EDTA). DNA is soluble in water and insoluble in ethyl alcohol. Adding ethyl alcohol to the top of the chemically treated fruit mixture dehydrates and precipitates the DNA from the solution. The DNA precipitates at the water/alcohol interface and can be collected.
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