Science 45

DNA is contained within the nucleus of plant cells, but can be extracted (removed) through various laboratory procedures.

One group of students isolated and extracted the DNA from a strawberry. Because DNA is not soluble in alcohol, the students used ethanol to separate the DNA from a mixture of blended cells. Their procedure is outlined below.

1. Place strawberries and homogenizing buffer* into a blender.
2. Heat the mixture at 55 degrees Celsius for 15 minutes
3. Cool the mixture to 10 degrees Celsius
4. Strain the mixture and collect the filtrate in a vial
5. Add ethanol to the mixture
6.Collect the DNA that accumulates in the ethanol layer

*The strawberries had to be blended in order to lyse (rupture) the cell and spill the DNA from the nucleus. The homogenizing buffer aides in this process.

Figure 1 shows the vial containing the strawberry mixture, ethanol and accumulated DNA. Students used a glass rod to collect the DNA from the ethanol layer.