First, we filled a beaker with 5 ml of liquid dish washing detergent, 0.75 of salt, and 45 ml of distilled water. Next, we rinsed the strawberry, put it in a plastic baggie and mashed it a ton. Then, we ran the contents through a filter to remove the big chunks. The liquid content dripped into a test tube. We then added an equal volume of ice cold alcohol to the test tube and began to slowly twirl the tube. A murky thick bubbly substance rose to the top of the solution in the test tube. This thick bubbly substance was the DNA.
Why did we do what we did?
The original crushing of the strawberry was essential because it increased the surface area and began to break down the membranes that are protecting the DNA.
The extraction buffer served the role of further breaking apart the phospholipid membranes. Also, because of the negative charge of the DNA, the salt was able to go in and break down the super phosphate groups, and separate the DNA. Also, this makes it less soluble in water. Making it so that it does not want to be with the rest of the water.
I am not sure why the alcohol was added, but my hypothesis is that it contributed by somehow combining with the DNA and is less dense than water, therefore making it float.
I want to continue to research this to learn how exactly this works. Anyway, it was super cool that we were able to separate the DNA from a fruit that I an familiar with, and I look forward to learning more about the processes of DNA.
