Strawberry DNA Extraction Lab Formal Write Up

Purpose :

This lab was conducted in order to show and analyze the way DNA is extracted.

Hypothesis:

If the lab is conducted properly then we should be able to view a visible amount of DNA from the strawberry and detergent mixture.

Variables:

The independent variable in this experiment is the strawberry mixture while the dependent variable is the amount of DNA extracted.

Procedure-summary:

Place a strawberry in a plastic baggy filled with the detergent mix and crush the strawberry, mixing the pulp with the detergent mix thoroughly, pour the detergent mixture into the funnel. Let the liquid from the mixture drain into the beaker then add the ethanol to the mixture.

Observations

The ethanol sat on top of the detergent due to its lighter density. Bubbles started rising as soon as the ethanol was added durn turning the liquid cloudy. The DNA grouped rapidly, taking no longer than two to three minuets total before slowing down and seeming to stop grouping.

The DNA itself looked like sputum or phlegm, and was easily extracted from the mixture and sticky to the touch. When the DNA was extracted from the test tube and the mixture was stirred, more DNA started to collect at the top.

Analysis

• As the strawberry is physically mashed into the detergent the cells are broken down and opened. The ethanol is else dense than the mixture and draws
  the now accessible DNA to the surface where it is viewable.
• In comparing the extraction of strawberry DNA compared to human DNA, given a sample of the same amount of cells, there would be more DNA extracted from the strawberry for it has eight sets of chromosomes while humans just have two sets.
• In real world situations DNA extraction would be used in something as complex as a murder investigation, in which DNA would have to be extracted to match a perpetrator to the evidence, or as simple as a pregnancy test.
• A single cotton thread can not be seen from 100 feet away, but thousands of cotton threads together in a rope would be visible. The same applies to DNA in this experiment. A single double helix is hard to view even with the most complex of microscope, but when thousands of sticky little DNA strands bind together in the ethanol solution they become visible to the human eye.
• Based on prior knowledge I know that the extraction of human DNA from mussel tissue is quite similar to the extraction of DNA from a strawberry and also ethanol based. That fact is to be expected for really there is no major cellular difference between strawberries and humans minus the fact that one is plant and the other is animal. Both are eukaryotic.

Conclusion

In the experiment, DNA was successfully extracted from a strawberry, demonstrating the process a real life scientists would possibly extract DNA from cells. The lab was intact successful for the group and I were able to extract a visible amount of DNA from the mixture.

There was really no source of error in this lab due to its simplicity. I feel in order to improve this lab, we should compare the amount of strawberry DNA to another fruit like a banana or kiwi. I personally learned the physical process of DNA extraction as well as what DNA looks like.