Kiwi DNA Extraction Lab Activity

DNA is present in the cells of all living organisms. This lab is designed to extract DNA from kiwi in a quantity to be seen and spooled. Why is it necessary to extract DNA out of a cell in genetic engineering? In order for genetic engineers to be able to work with DNA and transfer it into another organism, it must be first taken out of the cell. Fortunately, a DNA remains somewhat stable outside of a living cell allowing scientists the opportunity to work with and study without destroying it. .

Materials (per group of students) two beakers (250 ml) knife for cutting kiwi large spoon for mashing thermometer strainer water bath (60 C) distilled water dish soap kiwi table salt two test tubes (one per student) 99% ethanol

Instructions

1. Set up hot water bath at 55-60° C.

2. For each kiwi, make a solution consisting of one tablespoon (10 ml) of liquid dishwashing detergent and one level teaspoon (1.5 g) of table salt in a 250 ml beaker. Add distilled water to make a FINAL volume of 100 ml. Dissolve the salt by stirring slowly to avoid foaming. AVOID MAKING BUBBLES.

3. Peel the kiwi and cut it into small pieces. Add the pieces to the solution made in step two be held in the beaker (250 ml).

4. Put the beaker in a hot water bath (don't put the solution itself in the bath!) being held at 55-60C for 10-12 minutes. During this time, press the kiwi against the sides and corners of the beaker with the back of the spoon. Do not keep the mixture in the hot water bath for more than 15 minutes because the DNA will break down or denature.

5. Filter the mixture through a strainer into your second beaker. When pouring the mixture into the strainer, avoid letting foam get into the beaker.

6. Dispense the kiwi DNA solution into test tubes, one for each student. The test tube should contain about 10 ml of the solution. STOP! Before you can continue you must CLEAN UP YOUR STATION. Place your two test tubes in one beaker. Bring the rest of your materials to the front of the class. Wash them and place them in the appropriate spot. Once this is done, you may move on to Step 7.

7. Add COLD alcohol to the test tube to create an alcohol layer of roughly the same volume as the kiwi DNA solution dispensed in step 6. For best results, the alcohol should be as cold as possible (kept in freezer). When alcohol is added to the mixture, the components of the mixture, except for DNA, stay in solution while the DNA precipitates out into the a1cohol layer.

8. Let the solution sit for 2 to 3 minutes WITHOUT DISTURBING IT. You can watch the white DNA precipitate out into the alcohol layer. When good results are obtained, there will be enough DNA to spool on to a glass rod or a Pasteur pipette. DNA has the appearance of white mucus.

Sources

Montana State University Extension Service. (1996) Dining on DNA: An Exploration of Food. Biotechnology. Retrieved May 1,2002 from http://www.accessexcellence.org/AB/BAiDODpub/.

Ag Biosafety. (2001) DNA and DNA Extraction. Retrieved May 1,2002 from http://www.agbiosafety.unl.edu/educationldnax.htm

Office of Biotechnology, Iowa State University. (2002) DNA Extraction from a Kiwi. Retrieved May 1, 2002 from http://www.biotech.iastate.edu/publications/labyrotocols/DNA Extraction Kiwi.html Kiwi DNA Extraction Activity: Questions

1. There were four barriers that we needed to get through to reach the DNA inside the nucleus, how did we do this? Hint: Think about the structure of the plant cell.

1. ______

2. ______

3. ______

4. ______

2. What “ingredient helps the DNA precipitate? ______

3. Describe in your own words, what the extracted kiwi DNA looked like.

______

4. Do you think the DNA obtained was pure? Why or Why not? ______

5. Name the three properties of DNA that are demonstrated by this lab.

1. ______

______

2. ______

______

3. ______

______