1. What is the subunit or monomer of the DNA structure?;2. What are the three parts of this subunit/monomer?;3. Describe the appearance of the DNA you retrieved.;4. What is the role of the blender in this experiment?;5. What is the role of the salt and the shampoo in this lab?;6. Why were coffee filters (or cheesecloth) used within this experiment?;7. Why did you pour the solution with the DNA into the alcohol?;8. Why can't we see the double helix shape of the DNA?;Attachment Preview;DNA IN MY FOOD LAB.doc Download Attachment;DNA IN MY FOOD???;The Making of a Smoothie;Prepared by the Office of Biotechnology, Iowa State;University and then adapted by Mosley;In this protocol students will extract DNA from bananas;that have been blended with water. A portion of the;banana mixture is then treated with shampoo and salt;mixed for 5-10 minutes, and then strained through a;coffee filter. The filtrate is added to cold alcohol and the;DNA from the banana solution precipitates (becomes;visible).;Materials;2- 5 oz plastic cups;blender;plastic spoon for measuring and mixing;#2 cone coffee filter;20 ml of distilled water;clear-colored shampoo, such as Suave Daily;Clarifying Shampoo;3- bananas;table salt, either iodized or non-iodized;1- plastic transfer pipette or medicine dropper;1- sealed test tube containing 95% ethanol (grain;alcohol) or 91% isopropyl (rubbing) alcohol;1- container with ice for cold alcohol tubes;laboratory instructions;Lab Instructions;Extract the DNA;DNA is present in the cells of all living organisms. This;procedure uses household equipment and store supplies to;extract DNA from banana in sufficient quantity to be seen;and spooled.;The process of extracting DNA from a cell is the first step;for many laboratory procedures in biotechnology. The;scientist must be able to separate DNA from the unwanted;substances of the cell gently enough so that the DNA does;not denature (break up.);You will prepare a solution of banana treated with salt;distilled water, and shampoo (detergent). The salt allows;the DNA to precipitate out of a cold alcohol solution. The;detergent breaks down the cell membrane by dissolving;the lipids (fatty molecules) and proteins of the cell and;disrupting the bonds that hold the cell membrane together.;The detergent then forms complexes with these lipids and;proteins, allowing them to be filtered out of solution by;the coffee filter while leaving the cells' DNA in the;filtrate.;Procedure;1. In a blender, mix a ratio of one banana per one cup;(250ml) of distilled water. Blend for 15-20 seconds;until the solution is a mixture. (Your teacher is;doing this step for you);2. In one of the 5 oz cups, make a solution consisting of;1 teaspoon of shampoo and two pinches of table salt.;Add 20 ml (4 teaspoons) of distilled water or until the;cup is 1/3 full. Dissolve the salt and shampoo by;stirring slowly with the plastic spoon to avoid;foaming.;3. To the solution you made in step 2, add three;heaping teaspoons of the banana mixture from step;1. Mix the solution with the spoon for 5-10 minutes.;The salt enables the DNA strands to precipitate.);4. While one member of your group mixes the banana;solution, another member will place a #2 cone coffee;filter inside the second 5 oz plastic cup. Fold the;coffee filter's edge around the cup so that the filter;does not touch the bottom of the cup.;5. Filter the mixture by pouring it into the filter and;letting the solution drain for several minutes until;there is approximately 5 ml (covers the bottom of the;cup) of filtrate to test.;6. Obtain a test tube of cold alcohol.;7. Fill the plastic pipette with banana solution and add it;to the alcohol.;(DNA is not soluble in alcohol. 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 alcohol layer.);8. Let the solution sit for 2 to 3 minutes without;disturbing it. It is important not to shake the test;tube. 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 by using a pasteur pipette that has been;heated at the tip to form a hook, you can retrieve;some of the DNA.;Conclusion Questions;1. What is the subunit or monomer of the DNA;structure?;2. What are the three parts of this subunit/monomer?;3. Describe the appearance of the DNA you retrieved.;4. What is the role of the blender in this experiment?;5. What is the role of the salt and the shampoo in this;lab?;6. Why were coffee filters (or cheesecloth) used;within this experiment?;7. Why did you pour the solution with the DNA into;the alcohol?;8. Why can't we see the double helix shape of the;DNA?
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