108 Exarcise 12 DNA Extraction (avoid a. Pour the pea soup misture theough a cof
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108 Exarcise 12 DNA Extraction (avoid a. Pour the pea soup misture theough a coffe Sier or cheese closth into a small glas 4 Ad 2 tablepoons of liqguid dish detergent to the pea-soup misture and genty swin S. Let the soapy peas sit for 5 minutes on the lab bench to mix creating bubbles) in the glass beaker What does the soup do to the what pca-soup mixture? (Hint Think about the structure of the cell and components we will need to rupture to free the DNA.) 6. Pour the misnure into several tcs tubes, making sure to oaly fill cach one up 1/3 of the way 7. Add 1/8 teaspoon of meat tenderiaer into cach test tube and mix very gently (avoid creating babbles) 8. What purpose does the meat tenderizer serve in the DNA extraction? (Hint: Think about the con- densed structure of DNA in the nucleus that includes histone proteins 9. Tik each test tube and very slowly pour cold rubing alcohol down the side of the tube until you have a layer on top of the soapy peas. You'll need to add an equal amount of rubbing alcohol to the soapy peas What does the rubbing alcohol do to the soapy peas? (Hint: Think about water and its ability to act as a solvent on DNA.) 10. Let the test tube sit on the lab bench for five minutes. I1. Use a glass rod to pull out the long, stringy, white molecules you have created, being sure to stay away from the protein mass located at the bottom of the test tubes. If you don't see anything in the tubes, let it sit for up to an additional hour if time permits. You can also use the toothpick to search for any strands near the interface of the alcohol and the soapy-peas. What is the long, white, stringy molecule? Why can't you see a double-helix? Would thie DNA isolated from an animal cell look any different?Explanation / Answer
5. Soap is added because it contains the compound SDS (sodiumdodecyl sulfate) and it break down and emulsify the fat & proteins that make up a cell membrane.
8. The purpose of adding meat tenderizer as it acts as an enzyme to cut proteins just like a pair of scissors.The DNA in the nucleus of the cell is molded, folded, and protected by proteins.The meat tenderizer cuts the proteins away from the DNA.
9. As DNA is a long, stringy molecule so rubbing alcohol (70-95% isopropyl or ethyl alcohol) is added into the tube down the side so that it forms a layer on top of the pea mixture.It is poured until there is same amount of alcohol in the tube as pea mixture.Alcohol is less dense than water, so it floats on top.Then we look for clumps of white stringy stuff where the water and alcohol layers meet to extract DNA.
11. The long,stingy molecule is DNA.We cannot see double helix after DNA extraction because one cannot view a single strain of DNA as it is too small and cannot be viewed in naked eye.
The DNA molecule is structurally the same in all living things, including plants and animals. That being said, the product obtained from this extraction protocol may look slightly different depending on whether it was extracted from a plant or an animal.We may have more contaminants (proteins, carbohydrates) causing the DNA to appear less string-like, or the amount of DNA that precipitates may vary.
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