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Extracting DNA from a Strawberry

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Hana Jawz

on 26 October 2013

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Transcript of Extracting DNA from a Strawberry

Extracting Strawberry DNA
Dependent: Amount of DNA extracted from strawberries.
Independent: The size of the strawberries
Controlled: Time of which ethanol and strawberries are left together. All other materials and entire procedure.
Data Collection
Raw data
Background Summary
This experiment teaches us how to extract DNA from strawberries at a particular stage of ripeness. DNA is a molecule that controls everything in a cell. We managed to yield DNA by using simple household products and this technique can be done using all types of fruits and plants, not only strawberries. This investigation taught us to observe what the DNA looks like to the naked eye and we also learnt many scientific skills. This activity will demonstrate how DNA can be isolated from a strawberry using common household materials.
The aim of this task was to study about DNA molecules and observe what stage of fruit growth is the best to extract the largest amount of DNA.
2 average sized under-ripe strawberries
2 average sized ripe strawberries
2 average sized over-ripe strawberries
½ Cup of tap water
2 small, clear plastic cups
2 measuring cups-1 teaspoon, 1 cup
Paper towels (use for drying your other materials, number may very)
2 teaspoons of dish detergent
2 teaspoons of salt
1 Coffee Filter
1/3 cup of Rubbing Alcohol
Wooden Popsicle Stick
1 Plastic Bag

Put the strawberry into the plastic bag, seal it and gently smash it for about two minutes. Completely crush the strawberry. This starts to break open the cells and release the DNA.
In a plastic cup, make your DNA extraction liquid: mix together 2 teaspoons of detergent, 1 teaspoon of salt and ½ cup of water.
Add 2 teaspoons of the DNA extraction liquid into the bag with the strawberry. This will further break open the cells.
Reseal the bag and gently smash for another minute (Avoid making too many soap bubbles).
Place the coffee filter inside the other plastic cup.
Open the bag and pour the strawberry liquid into the filter. You can twist the filter just above the liquid and gently squeeze the remaining liquid into the cup.
Next, pour down the side of the cup an equal amount of cold rubbing alcohol as there is strawberry liquid. Do not mix or stir. You have just isolated the DNA from the rest of the material contained in the cells of the strawberry.
Within a few seconds, watch for the development of a white cloudy substance (DNA) in the top layer above the strawberry extract layer.
Tilt the cup and pick up the DNA suing a plastic wooden stick.
I think that the over ripe strawberry will yield the most amount of DNA that can be extracted than the other strawberries at their stages of ripeness (under-ripe and ripe).
Explaining the Hypothesis
The over-ripe strawberries might have the most extractable DNA because they are already soft and the isolation of the DNA from the other parts of the strawberry might not be as difficult as to the under-ripe and ripe strawberries.
The volume of DNA extraction from different strawberry fruits.

Group #
Data Processing
On the graph, I have taken the average of all four groups of each stage of ripeness and have plotted a graph according to this information. As you can see from the graph, the over-ripe strawberries yield the most extractable DNA, as I had predicted.
1. What is the relationship between the ripeness of the strawberry and the volume of DNA?
Ripe strawberries are an excellent source for extracting DNA because they are easy to pulverize and contain enzymes that help to break down cell walls. More importantly, strawberries have eight copies of each chromosome, so there is a lot of DNA to isolate.

2. Explain your answer?
The hormone also breaks down the fibers and softens the fruit which helps to increase the volume of extractable DNA.
The DNA forms between the alcohol layer and the strawberry extract layer beneath.
DNA is insoluble in alcohol and it precipitates. The DNA is a long thread-like molecule that interfaces the alcohol and the DNA solution.
Ripening is the process in fruit that causes them to become more edible. In humans and plants, the hormones are chemical compounds that help regulate growth processes. Fruit grows as hormones make its cell walls more elastic and expandable. Other hormones break down chlorophyll, allowing bright, appealing colors to develop. Hormones decrease the acidity of the juice and convert complex carbohydrates in the tissue into sweeter simple sugars.

1. Do you see weaknesses in the procedure?
The weakness in this experiment was that we could not compare and contrast one specimen’s DNA from another, which would have helped us recognize and realize the specifications of this particular entity’s DNA.

2. What are the sources of errors in the experiment?
The experiment instructions gave an impression of extreme easiness, as measurements were not required during the research nor were there specific prerequisites of other capacities or temperature. Impurities could have easily been carried in, and may have changed any aspect of the investigation

3. Suggest improvements to this investigation.
The improvements in this investigation would be to be given more class time towards extraction of DNA of different types of strawberries with dissimilar ripeness, as well as other sampling variety, for example, possibly onions, kiwis or other fruits and/or vegetables. I would like to also comprehend and recognize DNA on a microscopic level, through different measures via sophisticated equipment.

Thank you for watching!!
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