Extracting Onion Dna

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Extraction of DNA from an Onion

Molecular biologists and biochemists are involved with research in finding out as much as possible about the DNA in plants. DNA was discovered in the 1950’s, there still remains a lot to be known about it, especially how it is used to determine the physical traits that we all have, and how it regulates the workings of the body. deoxyribonucleic acid is a chemical, we can do reactions with it just like we can work with any other chemical. Experiment:

Note: You should write all observations from this lab in the observation section on the third page of this lab. These observations will account for a large part of your grade, so be neat and complete!

1)Prepare a buffer solution by pouring the following into a clean 250 mL Erlenmeyer flask:
-120 mL of water (distilled water, if available)
-1.5 grams of sodium chloride (table salt)
-5.0 grams of baking soda (sodium hydrogen carbonate)
-5.0 mL of shampoo or liquid laundry detergent

What buffer solutions are used for:
This buffer solution is used in this lab for several reasons. First of all, the saltiness and acidity (pH) of the solution is very close to that in living things; as a result, the DNA will like to dissolve into this solution. Secondly, the detergent is added to help break down cell walls in the onion cells. Cell walls in living things are made of long polar molecules with a “greasy” end and a charged end. Because detergent is used to break apart greasy particles in your clothes, it will also work to tear apart the “greasy” molecules in cell walls. It will be important that these cell walls break down in this lab, because inside the cell is where the DNA is.

2)Chill the buffer solution by placing the flask in a larger beaker filled with crushed ice and water.

Why we need to chill the buffer solution:
As important as DNA molecules are to life, they are still extremely fragile, and break apart easily when removed from cells. To slow...
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