DNA is a part of all living things. In this project, students will investigate whether DNA from an onion can survive if it is separated from other cell components. Research DNA found in plant matter before you begin this experiment. You will need to have several test tubes for this project. Place one strand of DNA from an onion in three different test tubes. Place the test tubes in three different environments: room temperature, refrigerator and someplace warm. After a few days, observe the onion strands under a microscope and see if any living DNA cells remain. Compare the different test tubes and record your results. What effect does temperature have on the DNA of an onion? How long did the DNA live in each environment, if at all?
Prepare for this experiment my chilling a bottle of rubbing alcohol in the freezer. Mix some salt, water and liquid dish detergent in a small bowl and set it aside. Line a funnel with some cheesecloth and place the funnel in a glass. Put some strawberries in a plastic bag, push out all the extra air and seal the bag. Mash the strawberries inside the bad for two minutes. Add three tablespoons of the salt and detergent mixture to the bag and push out all the air before sealing the bag. Squeeze the mixture again for one minute and pour the mixture through the funnel. Wait until there is no more liquid left in the funnel and throw away the cheesecloth. Pour the liquid from the glass into a test tube until it is one-quarter full. Tilt the test tube and slowly pour some of the chilled alcohol down the inside, Be careful not to let the two solutions mix. The DNA is found in the gooey white layer between the alcohol and the strawberry mixture. Collect a sample by dipping a bamboo skewer into the liquid just to where the two layers meet and pull it back out again. The gooey white liquid will cling to the skewer. Observe the strawberry DNA under a microscope.
Prepare one warm water bath (60 degrees Celsius) and one cold water bath (4 degrees Celsius). Prepare a solution of one tablespoon of liquid detergent and one-quarter teaspoon of salt. Add enough distilled water to make 100 milliliters. Chop one large onion and put it into a four-cup measure. Cover the onion with 100 milliliters of the salt/detergent solution. Put the onion mixture in the warm water bath and for 10-to-12 minutes, pressing the chopped onion mixture against the side of the cup with a wooden spoon. Transfer the mixture to the cold water bath for five minutes, pressing the onion mixture against the side of the cup with the wooden spoon. Filter the mixture through a coffee filter or four layers of cheesecloth placed over another measuring cup. Pour the filtered solution into the test tube until it is about one-third full. Add cold alcohol to the test tube, creating a 1-centimeter layer on top of the onion solution. Let the solution sit for two to three minutes, then insert a wooden skewer to collect the DNA from the layer formed between the onion solution and the alcohol. Observe the DNA under a microscope.
The purpose of this science project is to collect DNA from various household items. Combine one-half cup of spilt peas with salt and cold distilled water in a blender. Blend on high speed for 15 seconds. Pour the mixture through a mesh strainer with very small holes into a glass bowl. Stir two tablespoons of liquid detergent into the liquid from the peas and let the mixture stand for 10 minutes. Fill a test tube about one-third of the way with the peas-and-detergent mixture. Sprinkle a pinch of meat tenderizer or a drop or two of contact-lens solution into the test tube and stir gently. Pour rubbing alcohol into the test tube at about the same amount as the pea mixture. Take photographs of the DNA layer that forms between the pea mixture and the alcohol. Record your observations in your project journal. Repeat this procedure with other fruits, vegetables or meats, and record your results in your project journal.