But if you wound thousands of threads together into a rope, it would be visible at the same distance. How is this statement an analogy to our DNA extr...
BACKGROUND: DNA can be found in all living organisms. In this lab, you will extract the DNA of strawberries. Ripe strawberries are an excellent source for extracting DNA because they are easy to crush and contain pectinases and cellulases that help break down cell walls. Also, more importantly, strawberries are octoploid (meaning they have eight copies of each chromosome), so there is a lot of DNA to isolate. MATERIALS (per group): • 1‐3 strawberries • 1 test tube • 10ml DNA extraction buffer (soapy salt water) • One beaker • 20ml ice cold 91% isopropyl alcohol • Moistened coffee filter to use as funnel • Stir stick • 1 Ziploc bag Procedure: 1. Remove the green sepals from strawberries. 2. Place strawberries into a Ziploc bag and seal shut. 3. Squish (gently, make sure not to tear the bag) for a few minutes to completely squash the fruit…until liquefied!) 4. Add 10ml DNA extraction buffer (soapy salt water) to your baggie and squish for a few more minutes. 5. Filter through a moistened coffee filter (make a little divot to hold the strawberries), and collect liquid in your beaker. DO NOT SQUEEZE the coffee filter with strawberry solution. Collect as much fluid as possible.
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*This is when we will take notes After our notes, transfer the filtrate to a large test tube and your teacher will give you the ice cold isopropyl alcohol to add to your filtrate. PAY CLOSE ATTENTION when the alcohol is added. What do you see? The white fluffy cloud at the interface between the two liquids is DNA! Use the stirrer to wrap DNA around and remove DNA. CLEAN UP YOUR MESS. Place strawberry pulp & filter in the trash. Liquids go down the drain. Wash beaker and test tubes and return to the location you found them.
DNA Extraction Lab Analysis Questions (use BEST writing skills): 1. Pectinases and cellulases are found in strawberries, what kind of organic molecule are these? __________________ 2. What was the purpose of mashing up the strawberry?___________________________________________________ _______________________________________________________________________________________________ ___________________________________________ 3. Why did use soapy water? (hint: why do you use soap when washing? What does it dissolve?) __________________ _______________________________________________________________________________________________ _______________________________________________________________________________________________ 4. Once you were able to gather the DNA, what did it look like?_____________________________________________ _______________________________________________________________________________________________ 5. A person cannot see a single cotton thread four classrooms away. But if you wound thousands of threads together into a rope, it would be visible at the same distance. How is this statement an analogy to our DNA extraction? ___________________________________________________________________________________________ ___________________________________________________________________________________________ ___________________________________________________________________________________________ 6. Is DNA found in all living/once living cells? (yes or no) How do you know?___________________________________ _______________________________________________________________________________________________
