Dna Extraction example essay topic

DNA EXTRACTION In extracting chromatin from the cells of wheat germ there are seven steps to follow. The optimal cell to use would be the polyploid al eukaryotic. Eukaryotes have nucleus membrane-bound organelles, while prokaryotic does not. The polyploid al eukaryotic cell has DNA that is held in the nucleus while the prokaryote has DNA that floats freely around the cell.

The DNA of eukaryotes is more complex and extensive than the other. Prokaryote is a bacterial cell that usually has DNA in one large strand and only has one chromosome while the eukaryotic cell has more than one chromosome and is considered to be a higher organism. Prokaryotes have an outer wall that prevents them from bursting or collapsing due to osmotic changes. With that said, during the buffering stage the cell could not be broken and the DNA could not be extracted. When you add the surfactant it softens the cell and the soap dissolves and breaks down the lipids and proteins in the phospholipid bi layer. Much like dish detergent does to greasy dishes.

Lipids are insoluble in water, the detergent reacts with the cell and causes the molecular contents to fall out much like hydrolysis. Without this you could never complete the extraction. Then you add the baking soda (buffer) to the test tube. Buffer is defined as a substance that tends to resist pH changes of a solution, thus stabilizing its relative acidity and basicity. The baking soda will extract the DNA, nuclear membrane and envelope out of a cell and keep it unchanged in the solution.

The baking soda must keep the pH levels at a neutral place similar to the way pool chemicals work together. If we didn't buffer the solution we would end up with trash. Next you add the meat tenderizer. I did further research and found that the "hydrolyzing protein (enzyme) known as papain can either be used as trace metal carrier or a sequestering agent that reacts with ions to form soluble complexes".

2 Both temperature and pH can bring about a change in polypeptide shape. When a protein loses it normal configuration it is called denatured. The tenderizer must eliminate the proteins, the membrane and envelope allowing the DNA to free itself from the tight coil. In the last step, you add ice-cold alcohol. When you add the freezing alcohol to the hot test tube you will cause precipitation.

Water is a polar molecule and when mixed with alcohol the ethanol's reaction with the DNA changes it from a polar to a nonpolar state. Therefore, it is stuck between two polar liquids and it forms its own layer. The DNA is not soluble in the alcohol unlike the soap. Only the DNA that directly contacts the alcohol becomes nonpolar and is near the top can precipitate out of the detergent but stay under the alcohol, where it is not soluble and therefore you can see the strand of DNA.

There are three steps that were completed: homogenization, , and precipitation of the DNA. Basically, the extraction could not occur without all the steps being followed and the chemical reactions that each part causes. The hot water, cold water, baking soda, alcohol, and meat tenderizer all play a part in the chemical process that DNA extraction requires. Without one you couldn't obtain the DNA.

The research Was interesting and I learned more about the cell functions by doing this paper. 1. Mader, Sylvia. (2001).

Biology (7th edition). McGraw-Hill, Inc. 2.. sid well. edu / us /science. html 3. web web cell. html.