1.  PUT ON YOUR SAFETY GLASSES!  Put the strawberry in the baggie.  Squeeze out all the air and seal shut.  Smash up the strawberry into pulp.  Try to get it all smashed up well. Be careful not to break open the baggie.

2.  Open the baggie and add 10 mL of the buffer solution.  Blend it together well, but try to create as few bubbles as possible.

3.  Place the cheesecloth inside the funnel and put it into the test tube.  Open the baggie and strain the strawberry mixture through the cheesecloth into the test tube.  You may gently squeeze the strawberry pulp to get out some more juice, but don’t let any pulp get into the test tube. You need about 1 inch (2.5 cm) of liquid.

5.  Tilt the test tube and using the pipette, slowly add enough alcohol to double the volume of liquid in the test tube.  Gently tilt and turn the test tube. You should see bubbles and white cottony material develop in the alcohol layer. This is the DNA!

*You can find online information for extracting DNA out of many living things, including onions, green peas, and cheek cells. Strawberries are used because they have 8 sets of chromosomes instead of 2, making more DNA readily available.  Dried green peas are also named as having a lot of DNA in them.

**Buffer solution can be made ahead of time as follows:

950 mL water

50 mL liquid dishwashing detergent

2 teaspoons salt

1 teaspoon meat tenderizer (you can substitute contact lens solution, and some instructions leave this out altogether…maybe depends on what fruit/vegetable you’re using?)

***Many instructions say to chill the alcohol for increased yield.

BOOK C, p. 26

Draw an example of a strawberry cell (plant cell).  Where is the DNA located in the cells of a strawberry?  Label and mark the location of the DNA inside your cell.

What are the cellular structures that serve as barriers to getting your DNA out of the cell?  List them here and label each structure on your drawing above.

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A person cannot see a single cotton thread 100 feet away, but if you wound thousands of threads together into a rope, it would be visible at some distance.  How is this statement an analogy to our DNA extraction?

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If you wanted to extract DNA from a living person, what cells would you use and why? (Is the DNA the same in any cell in the human body?)

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List two reasons why a scientist might want to study the DNA of strawberries.

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