1195 WordsOct 18, 20145 Pages
Much can be learned from studying an organisms DNA. The first step to doing this is extracting DNA from cells. In this experiment, you will isolate DNA from the cells of fruit. Materials (1) 10 mL Graduated Cylinder(2) 100 mL Beakers15 cm Cheesecloth1 Resealable Bag1 Rubber Band (Large. Contains latex pleasewear gloves when handling if you have a latex allergy).Standing Test TubeWooden Stir StickFresh, Soft Fruit (e.g., Grapes, Strawberries, Banana, etc.) ScissorsDNA Extraction SolutionIce Cold EthanolYou Must ProvideContains sodium chloride, detergent and waterFor ice cold ethanol, store in the freezer 60 minutes before use. Procedure If you have not done so, prepare the ethanol by placing it in a freezer for approximately 60 minutes.…show more content…
Let the test tube sit undisturbed for 2 - 5 minutes. You should begin to see air bubbles form at the boundary line between the ethanol and the filtered fruit solution. Bubbles will form near the top, and you will eventually see the DNA float to the top of the ethanol. Gently insert the stir stick into the test tube. Slowly raise and lower the tip several times to spool and collect the DNA. If there is an insufficient amount of DNA available, it may not float to the top of the solution in a form that can be easily spooled or removed from the tube. However, the DNA will still be visible as white/clear clusters by gently stirring the solution and pushing the clusters around the top. Post-Lab Questions What is the texture and consistency of the DNA DNA is viscous and greasy. Why did we use a salt in the extraction solution High salt makes DNA less soluble in water. In order to dissolve, the water needs to interact with the DNA. Since DNA is quite large, it needs to interact with lots of water for this purpose. When you add salt, the water preferentially interacts with the salt (its small, and can move around in solution easier than the DNA can). This makes it so there is less water available to interact with the DNA and it becomes less soluble. Is the DNA soluble in the aqueous solution or alcohol DNA is less soluble in an alcohol such as isopropanol than it is in water. This is because alcohols are non-polar, whereas water is polar. The polar

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