DNA Extraction Lab
Purpose: To compare the amount of DNA extracted from two different species, despite using the same method. Hypothesis: I predict that the liver will produce a higher quantity of DNA than the strawberry. This is because I believe that animals have a higher DNA yield because our structure is more complex than a plant’s structure. Materials:
-Sample of Strawberries
-Zip lock bag
-DNA extraction buffer
-Double ply cheese cloth
-Two test tubes
-Test tube rack
-Sample of meat
-Two small beakers
Procedure: Refer to page, 224
1. Repeat procedures for a small sample of meat and a sample of fruit. 2. Place fruit sample in a zip lock bag. Remove air and seal the bag then use hands to smash and crush the fruit. 3. Add 10ml of extraction buffer, seal the bag and mix the two together very well with your hands. 4. Pour the mixture through the cheese cloth into a test tube. Squeeze out the liquid but not the pulp into a small beaker. 5. Fill the test tube ¼ with the liquid mixture.
6. Slowly drizzle 10ml of cold ethanol into the test tube so that it floats on top of the mixture. 7. A white stringy precipitate forms between the two liquids, this is the DNA. 8. Twist it on to a glass rod. Observe and describe the extracted DNA and weigh it. 9. Weigh the rod separately to find the weight of the DNA 10. Repeat all the steps for a similar size of meat.
| Weight of Rod + DNA
| Weight of DNA
| -White/transparent liquid.-Thick liquid.-Flexible.
| -Opaque liquid.-Thick liquid.-Light brown/white in colour.-A lot more DNA produced than the strawberry.
Analysis: Refer to page, 224-226
c) The DNA “Stuck” to the glass rod because of their charges. The glass is positively charge and the oxygen in the DNA is negatively charged. When the two...
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