Solved by a verified expert:Unit 3, Lab 2DNA Extraction from a BananaIntroduction:As you are learning in Unit 3, DNA is the blueprint for life and resides in the cells of all livingthings. In this experiment, you will extract DNA from a banana using a few basic ingredients,many of which you may already have around the house.In order to extract the DNA from cells, the cell and nuclear membranes must first be broken opento allow the release of DNA. In a laboratory setting, this is done by mixing cells with a specifictype of detergent, which breaks apart (or lyses) the cell and nuclear membranes. In this case, wewill use kitchen dish detergent, which is a close cousin to the detergent used in labs. In order tothen isolate the DNA away from cellular debris, salt and alcohol are used. DNA is polar, andtherefore readily dissolvable in water. Salt and alcohol, however, reduce the polarity of theDNA, causing it to separate (or precipitate) away from the water and become visible to the nakedeye as long, milky-looking strands. We will use table salt and 70% isopropyl alcohol (alsoknown as rubbing alcohol) for this step.Materials:BananaZiplock bagMeasuring spoons and cupsIce-Cold Alcohol (70% Isopropyl Alcohol, or rubbing alcohol, stored in freezer for at least anhour before the experiment)WaterTable SaltLiquid Dishwashing DetergentCoffee filter (paper towel can be substituted)Toothpick, wooden skewer or wooden coffee stirrer (optional)Instructions:1) Place a 1-2 inch section of banana into a ziplock bag. Using your fingers, knead andsqueeze the banana until it is a mushy consistency and no solid form remains.2) Fill a measuring cup with ½ c lukewarm or room temperature water and add 1 tsp salt.Stir to dissolve most or all of the salt.3) Add the salt water mixture to the banana, seal the bag, and shake gently to mix for 45seconds to mix.4) Add 1 tsp liquid dish soap and again shake the bag gently for 45 seconds. Shake oragitate gently to prevent too much dish soap foam from accumulating.5) Set a coffee filter (or paper towel) over the top of a clear, narrow glass container, (adrinking glass will do), pushing the center of the coffee filter down into the containerslightly, making a well, and overlapping the edges over the sides. If necessary, use arubber band to hold the filter in place.6) Pour the banana mixture through the filter until most liquid containing the released DNAhas passed through, trapping the banana in the filter. You may have to pour the liquidseveral times, waiting for it to drip through each time before adding more. You may alsodiscard the coffee filter and get a new one as the original one fills with banana making itmore difficult for the liquid to flow through. 7) Tilt your glass container at an angle and very slowly pour the ice cold isopropyl alcoholdown the inside of the container so that it slowly forms a layer on top of the DNAmixture. Continue to pour until the layer of alcohol is approximately 1-2 inches thick.8) Observe the interface where the food mixture and alcohol meet for approximately 5-10minutes. The DNA will begin to accumulate in the alcohol layer as a milky-white,stringy substance. You can gently swirl a toothpick or wooden skewer to observe theclumps of DNA, doing your best to not disturb the interface. Allowing the experiment tosit for longer (up to an hour) will allow for more DNA accumulation.9) Take a picture of your results and upload it with your written assignment (below).To Submit For a Grade:Please complete the following short answer questions and submit them for your grade, alongwith a picture of your completed experiment.Please describe the purpose for each of the following reagents (ingredients) in your experiment.In other words, why are these necessary in the DNA extraction process? Please use completeand descriptive sentences when formulating your answers.Banana:Salt:Dish Detergent:Isopropyl Alcohol:
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