DNA Extraction from Kiwifruit
Student Instructions
Introduction
DNA is present in the cells of all living organisms. This procedure is designed to extract DNA from
kiwi in sufficient quantity to be seen and spooled. . Because DNA exists inside of cell and ultimately
inside of the nucleus proteins must be denatured to locate the DNA. There are different proteins
that form the membranes of the organelles and that allow DNA to coil so that it can fit inside of
the nucleus. This activity is ideal for students to work in pairs, but each student will have a tube of
DNA at the end.
Some questions to get you thinking about today's lab:
1. One way to purify a molecule is to get rid of everything but that molecule. If we want to
isolate DNA from kiwifruit, what do we have to get rid of?
2. What materials would you use to do that?
3. What can we do with the DNA once we've purified it?
Materials
• ziplock bags
• jar or beaker that fits strainer or funnel strainer or funnel
• cheese cloth (cut to cover the funnel)
• ice water bath (a large mixing bowl works well)
• extraction solution
• kiwifruit
• cold 95% ethanol or isopropanol
• small test tubes (1 per student)
Protocol
1. Get 6 pieces of kiwi and put them in a ziplock bag.
2. Add 20 ml of extraction solution to the ziplock bag. Make sure the bag is closed
without much extra air. Mush the kiwi thoroughly but carefully so the bag doesnÕt
break, for about 5 minutes. What does mushing the kiwi do?
3. What do you think the extraction solution is? What does it do to the kiwi?
4. Cool the kiwi mixture in the ice bath for a minute. Then mush the kiwi more. Cool,
then mush. Repeat this several times. Why do we cool the mixture?
5. Filter the mixture through the cheesecloth. All the groups can combine their
mixtures at this point, to filter together. What is being filtered out? What is going
through the filter?
6. Dispense approximately 2 ml of kiwi solution into each test tube, one for each
student.
7. Being careful not to shake the tubes, add approximately 2 ml of cold 95% ethanol to
each tube. What do you think the ethanol does? Why do we want it cold?
8. Take a look at your tube. What do you see in the top portion of the liquid?
