DNA Extraction Laboratory (DOC) by pptfiles


									DNA Extraction Laboratory Notebook Lab Introduction:  Describe the importance of DNA in a cell.  Define DNA extraction Hypothesis: If DNA is so important than predict what percent of a cell’s mass is made of DNA. Procedure:  Measure the mass of your strawberries.  Go through the following steps to extract DNA from the strawberries: 1. Take 2-3 strawberries and put in a mortar. 2. Add 2 spoonfuls of salt and two large squirts of dish soap. Then add an equal volume of tap water to the dish soap and salt. 3. Using the pestle mash the strawberries and other materials until they are liquidy. 4. Put cheesecloth (multiple layers) over the beaker. Pour strawberry liquid into the cheesecloth and let the liquid drain through. Then squeeze cheesecloth to get the remaining liquid out. 5. Wait 5 minutes. The dish soap and salt need time to react with the strawberry cells. Answer the questions on your sheet about why you might be adding the salt and dish soap. Think of where the DNA is in a plant cell and what you might need to do to get it out. 6. Slowly pour equal volume of cold alcohol into beaker. (3050 ml). 7. Let stand on top of strawberry liquid for 5 minutes. Why does it remain on top? 8. Spool the DNA that has precipitated onto a glass rod. Observe the properties of material. 9. Measure the amount of DNA collected and record in grams. In your lab notebook answer the following: -Why do you grind up the fruit with salt? -Why do you mix the dish detergent? -Why doesn’t the alcohol mix with the strawberry solution? Data and Observations:  Describe what DNA looks like. Data table. Mass of strawberries Mass of DNA % of Strawberry Mass made of DNA  Show your calculation. Conclusion:  Respond to your hypothesis. Use the statement the data supports (or rejects) the hypothesis that…because… Give data to support your conclusion.  Is the DNA completely purified? Explain why or why not? What else might there be besides DNA?  If this was human hair, could you tell the difference between two people’s hair by simply doing a DNA extraction? Why or why not?  Why do you think being able to extract DNA is the first step in many molecular experiments? Use google to find some examples of molecular experiments.

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