1. The salt contributes positively charged atoms that neutralise the normal negative charge of DNA. Salt is used at a high molarity due to the fact that it precipitates all of the proteins out. DNA is insoluble in low molar salt solutions but soluble in low molar salt solutions thus keeping the DNA in solution. 2. blending the onion will homogenize the mixture and it helps with the breakdown of the cell walls. Blending saves one the time and effort of using a motar and pestle, however it may break a lot of the DNA which is not favourable as one needs a lot of DNA for the extraction. 3. The enzymes in the soap are used to break down the lipid (fat) molecules of the cell's nuclear membranes releasing the contents of the cell crucially including the DNA. These enzymes in the soap are what break down grease while washing dishes. 4. The DNA does not dissolve in this alcohol but rather pushes up through and out of the solution or precipitates. It is less dense than water or cell scum which is what settles to the bottom of the glass so it floats up into the alcohol layer, where you see it as a snotty, string-like substance, with small bubbles formed on it. 5. Because protein is stored in them for the nutrition of the new plants. 6. It is too small to be seen with the naked eye. What you extracted is millions of strands of DNA. In addition to that, whilst the substance was heated, the DNA got denatured which results in it looking more like a ladder than a helix. 7. Most of the DNA extracted during this proccess comes from the nucleus of the cell.
The purpose of this experiment is to extract DNA from a variety of cells (Onion cells in particular) and see DNA molecules. This will show that, contrary to popular opinion, DNA is not just found in blood cells, but in a variety of tissues. Prior knowledge should include the fact that cell membranes are layers of lipids, or fat molecules, that DNA is found in the nucleus of a cell, and that enzymes...
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