Please follow these directions Ms Bramlett has lost

Please follow these directions Ms. Bramlett has lost her voice. In order for us to do lab today, you must be very quiet and cooperative. When I ring the bell, please look up at the screen for instructions. Thank you for helping out today by following these easy directions!

DNA Extractaction

Introduction: Page 16 • DNA must be extracted from blood samles from Jack and Jill Miller to be tested for the presence of the hemocratosis mutation. Many of the steps involved in extracting DNA from a strawberry are similar to steps used in DNA extraction from human tissue.

DNA Extraction • DO you think that you have ever eaten DNA?

• All food items contain material from plants and animals and contain the DNA of those once living organisms

Lab Safety • • • Wear goggles No horseplay PLEASE be quiet Stay at your own lab station Do not turn around and talk to other students in different lab groups. • Throw all trash away in appropriate container.

Directions • Place coffee filter over the top of the plastic cup and create an indention in the middle of the cup. Secure the filter with a rubber band. • Set aside • Each person at the group may do one.

Instructions • Place your strawberry in to the baggie and remove as much air as possible, then seal • NOTE: Strawberries are plants so they have both a cell wall and a cell membrane. • Recall that DNA is in the nucleus

Instructions • Mash the strawberry with your fingertips for two minutes. BE CAREFUL NOT TO BREAK THE BAG. • In order to break open the cell wall so we can get to the DNA, we must macerate the strawberry. This means to crush or grind it.

Instructions • Maceration separates cells into smaller clumps of cells and ruptures plant cell wall.

Instructions • Use a graduated cylinder to measure 15 m. L of lysis solution from bottle. • Add the 15 m. L of lysis solution to the bag and close it again. • Mix and mash the contents for one minute.

Instructions • Lysis: to burst or rupture • Cell membranes are made of lipids and lipids are fats. • What is used to remove fats/grease from dishes?

Instructions • Soap acts as a lysis solution to remove the grease from pots and pans.

Instructions • Open 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 to the cup. • Take care not to knock over the filtration cup in the process.

Instructions • Read page 22: Why extract?

Instructions • Observe the reddish liquid as it drops into the cup. • Where is the DNA found? Is it in the filtrate in the cup or in the solid matter that remains in the filter?

Instructions • DNA is found in both places. The DNA that will be extracted is in the fitrate collected in the cup. • DNA is soluble in water but not in other substances.

Instructions • Remove the filter by holding the filter at the top of the cup and rolling the rubber band down the cup. • Lift the paper with strawberry solids and throw in the garbage can. • Be careful that solids do not drop into the cup by keeping the edges of the filter together during removal

Instructions • Pour 20 m. L of ice-cole isoporpyl alcohol into the 50 m. L skirted tubes. DNA is less soluble in alcohol and will clump together, or precipitate when placed in an alcohol solution.

Instructions Watch the cup closely as translucent strands of DNA begin to clump together at the interface between the alcohol and the strawberry extract. DNA looks like white clumps on the surface.

Instructions • Insert the wooden stick into the extraction liquids gently. • Slowly and carefully twist the wooden stick and wind the DNA around the stick like thread on a spool. • Remove the DNA from the tube and observe.

Instructions • Wooden sticks and glass rods are used to spool DNA because DNA adheres to both wood and glass. In some cases, the lysis solution causes the DNA to shear or break into smaller pieces. • Shredded DNA is hard to spool.

Instructions • Place 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

Instructions • How stable to you think DNA would be in it was not stored in alcohol?

Instructions • Storing in alcohol holds DNA molecules together longer than storing in other liquids. • Enzymes that break down DNA are found on the skin and over time these enzymes may cause the DNA sample to disintegrate.

Questions for you to answer Copy on paper and write answer. • • 1. 2. 3. 4. What is DNA Where do you find DNA How is DNA extracted from plant cells? What does DNA look like?

CLEAN UP • • Throw all trash away. This includes: Cup with filter Wooden stick Rubber band Baggie Please place skirted tube in the sink Please wipe up any mess on your table You may keep the micro-centrifuge tube of DNA.

Thank you! • Thank you for helping out today while I could not talk! • I hope you enjoyed this lab and learned a little about DNA extraction. • Have a great rest of the day!