1. How can I extract DNA from a plant cell?

2. Even though DNA is 100,000 times as long as the cell, it only takes u about 10% of the volume within the cell. This is because the DNA is highly coiled and tightly packaged. Long strands of DNA wrap around special packing proteins (like thread wraps around a spool).

3. DNA in the relaxed state is not visible. During cell division DNA coils even tighter into structures known as chromosomes, that are visible under a light microscope. DNA’s structure is usually a double helix. The DNA ladder tends to twist into a coil because of the chemistry of the atoms and the bond angles between them.

4. Extracting DNA DNA extraction involves 5 major steps: 1.Maceration 2.Lysis 3.Filtration 4.Precipitation 5.Spooling

5. Releasing DNA from Strawberries To release DNA from strawberry cells, the cell wall, cell membrane and nuclear membrane must be broken. This is accomplished by maceration and lysis.

6. Maceration and Lysis Maceration is mechanically breaking apart the tissues into separate cells. Lysis is used to rupture the cell membrane so the DNA can be released. We will use soap an salt as our lysis solution. This helps strip away additional proteins associated with the DNA molecule

7. Filtration Filtration allows the solid material left from maceration to be separated from the liquid components that have been created by lysis. We will use coffee filters for filtration.

8. Precipitation During precipitation, strands of DNA clump together and the DNA eventually becomes visible. We will use isopropanol to make the DNA fall out of the solution.

9. Spooling DNA will stick to wood and glass. We will use wooden sticks for spooling. To spool, gently twirl the wooden sticks through the DNA clumps to collect as much DNA as possible.

10. Steps in DNA Collection 1. Place a coffee filter over the top of the plastic cup, creating an indention in the middle of the cup. Secure the filter with a rubber band.

11. Steps in DNA Collection 2. Place a strawberry into the sealable sandwich bag, close the bag after removing as much air as possible. 3. Mash the strawberry with your fingertips for two minutes, being careful NOT to break the bag. (This is the maceration part)

12. 4. Use a graduated cylinder to measure 15 mL of lysis solution from the beakers. 5. Add the 15 mL of lysis solution to the bag and close it again. Mix and mash the contents of the bag for 1 minute. (This will help to burst or rupture the cell membranes so DNA can be realeased.)

13. 6. Open the bag and tilt the bag, carefully pouring the entire contents of the bag into the coffee filter. Slowly let the liquid drip through the filter into the cup. Take care not to knock over the filtration cup in the process. Observe the reddish liquid as it drips into the cup

14. 7. Remove the filter, by holding the filter at the top of the cup and rolling the rubber band down the cup. Lift the filter paper with strawberry solids and dispose of it in the garbage. Be careful that solids do not drop into the cup by keeping the edges of the filter together during removal.

15. 8. Pour 20 mL of ice-cold isopropyl alcohol in the 50 mL skirted tubes. 9. Tilt the cup of strawberry juice carefully and slowly pour the strawberry liquid into the cold alcohol. DO NOT MIX!!!! The DNA will precipitate and mix where the two solutions meet.

16. 10.Watch the cup closely as translucent strands of DNA begin to clump together in the interface between the alcohol and strawberry extract. 11.Insert the wooden stick into the extraction liquids. Slowly and carefully rotate the wooden stick, winding the DNA around the wooden stick like thread on a spool.

17. 12. Place the DNA in the micro-centrifuge tube. The DNA will remain as a precipitate and will be stable for many years in the tube. Close the lid tightly to prevent evaporation.

18. Questions A. What is DNA? B. Where do you find DNA? C. How is DNA extracted from plant cells? D. What does DNA look like?