DNA Extraction Lab

DNA Extraction: Strawberries

To further our understanding of DNA and genetics, we extracted DNA from a strawberry in DLC.

Hypothesis: The strawberry’s DNA will be shaped in the form of a Double Helix because in living organisms, DNA is always a Double Helix. Also, by smashing the strawberry, the cell wall will be broken as well as the cell membrane, and this will allow easy access to the nucleus and the DNA inside.

Procedures: Put a strawberry that is cut into small pieces in a plastic bag, and seal it. Crush the strawberry with hands for a few minutes until it is mostly liquid. If the bag breaks, then place the broken bag inside a new bag, and seal the new bag, and continue crushing the strawberry. Using a pipette, add 10 mL of lysis buffer (salt and soap solution) to the smushed strawberry. Mix the lysis buffer into the strawberry with your fist and fingers. Place the test tube in the beaker, and place the funnel on top of the test tube. Wrap the cheesecloth around the funnel. It is beneficial to create a little dip in the cheesecloth, so that when the strawberry is being poured through the cheesecloth is goes down instead of splashing all over the place. Pour the strawberry into the cheesecloth, and let it drip into the test tube. Wash the pipette, and use it to add 3 mL of cold ethanol into the test tube. Use a toothpick to gently swirl the solution, and pick up DNA.

Data and Analysis:

This is a diagram showing how the lab was set up.

This is what the strawberry looked like after smashing it for the first time.

This is the Lysis Buffer that was used to break through the cell wall and membrane. It acts like the lysosomes do in a eukaryotic cell. The lysosomes go into self-destruct mode.

This is the strawberry mush dripping into the test tube after the lysis buffer was mixed in.

By pinching the corners of the cheesecloth, it sped up the process of extracting strawberry juice. The cheesecloth served as a sieve so that there would be no seeds mixed with the DNA.

Questions:
1. D, A, C, B

2. The DNA looked like big glob of white slime. It was a little bit curly. This is because it is shaped like a Double Helix.

3. By adding the ethanol, the DNA was able break free from the nucleus.

4. It is because DNA is extremely tiny. However, when there are large clumps of it (like the DNA in strawberries), it is easier to see.

5. It is important for scientists to remove DNA from organisms because we can learn more about evolution from the past, and we can gain a better understanding of the human body.

6. There is DNA in food because every living thing contains DNA, and almost every food is made up plants. Plants are living organisms, so they have DNA.

Conclusion: This experiment was very interesting because I got to witness DNA. I was not just looking at a computer diagram. I was looking at a real strand of DNA. My hypothesis was accepted because the smashing of the strawberry was the process that was done to break open the cell. I learned what a DNA looks like, and I learned how to extract it. This lab works especially well with strawberries because they have an octet amount of chromosomes, so there is a large chance that you will find chromosomes. However, my group did not find as much DNA as the other groups. This may be because we did not receive as many strawberries as they did. In conclusion, extracting the DNA from a strawberry helped me learn more about DNA and chromosomes.