The document is a science fair research paper about extracting DNA from fruits. The student chose five fruits - strawberries, banana, kiwi, raspberries, and blackberries - to determine which has the most DNA. To do this, each fruit will be mashed and mixed with water, soap, and rubbing alcohol. The DNA will precipitate out of solution and the student will count the amount of DNA from each fruit to find the fruit with the most. The purpose is to learn about the composition of fruits at a molecular level.

1. Laura Valades Sacred Heart School
Science November 7,2014
Research Paper
For the Science fair, my experiment is figuring out which fruit has the most
DNA out of a couple of fruits. These fruits are Strawberries, Banana, Kiwi,
Raspberries, and Blackberries. My five questions are what makes up a fruit, Why are
fruits juicy, why are certain types of fruits more acid than others, why do fruits have
seeds, and why is there sugar in fruits. I chose this project because I think that
seeing how the fruit is made up and how it is set up is interesting.
A fruit is generally divided into 2 layers, the Pericarp and the Seed. In the
Pericarp there are 3 things that are called the Exocarp, the Mesocarp, and the
Endocarp. The Exocarp is made up of the part of the fruit that you can see before
you cut it, the shell in other words. The Mesocarp is made up of the layer after that
which is usually the thickest layer. After that comes the Endocarp which is made up
of the last layer that is part of the Pericarp which is also the littlest layer of the
pericarp. The seed is after the pericarp.
The reasons that the fruits are juicy is because water passes across a
semipermeable membrane to equalize the water on both sides of the fruit. If the
water on both sides of the fruit is equal then the water stays where it is and does not
move. If the water is not equal, then the water will equal it self out by going to the
side where there is less water. If there is too much the water will go away until
there is the same amount of water on both sides. The juice then leaves the fruit and
mixes with the sugar and makes it juicy.
Citric acid is what makes fruits acid. It is most commonly associated with
citric fruits, but it also occurs in other fruits that are not citric. Citric acid has a bitter

2. flavor, and can be tart. It also contains no vitamin C. Berries have less citric acid than
citric fruits, but they still contain some. It is not as prominent in berries as it is in
citric fruits, but the acid is still there. Out of all these berries, blueberries are the
berry that has the least amount of citric acid. Tomatoes are considered one of the
fruits with the most citric acid. Tropical fruits such as the pineapple also contain an
extremely high amount of citric acid.
The reason that fruits have seeds is because it is a way of producing mor e
fruits. The tree "drops" the fruit. Animals go to the fruit, they eat it, and then they go
to a different place and the things that cannot be digested like the seeds go out of the
body. The seeds are deposited away from the original plant, and then that seed
grows into a plant and produces more fruits that then helps it repeat that same
process over again. Different plants have different ways of ensuring that plants
survival.
Fruits have sugar, in other words fructose. If you eat a fruit, nothing will
happen to you because it has sugar. It has natural sugar. Fructose is bad in large
quantities, and while fruits have sugar, they have almost no sugar. It is impossible
to intake too much Fructose by eating a piece of fruit. For most fruits, it takes a
while for the sugar to have an effect on the body due to the amount of time it takes
to digest the fiber, such as soluble fiber. Fruits also fill up you up due to the large
amount of fiber that one piece of fruit contains. For example, an apple has 23 grams
of sugar and only 13 grams of that are fructose sugar.
For my science fair project, I plan to extract DNA from five fruits. These five
fruits are strawberries, banana, kiwi, raspberries, and blackberries. I will mash the

3. fruit, and put it in a tube. Then I will add water, and soap. After that I will add
rubbing alcohol and I will see the DNA precipitates rise. Due to the amount that rises
in each fruit sample, I will determine which fruit is the one with the most DNA. I will
do the same thing with each fruit several times so I have a couple samples of the
fruit DNA.

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