Dische essay

A white onion was used for the experiment. Deoxyribonucleic acid isolate was the seeable consequence. Different chemical trials were performed on the Deoxyribonucleic acid isolate.

Dische essay

Get Full Essay Get access to this section to get all help you need with your essay and educational issues. A white onion was used for the experiment.

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After several processes, DNA isolate was the visible result. Different chemical tests were performed on the DNA isolate, namely: Visible results were then noted.

It occupies a central and critical role in the cell as the genetic information in which all the information required to duplicate and maintain the organism. Today, Scientists can analyze DNA from minute samples of blood, hair roots and saliva, but before they can analyze DNA, scientists must be able to extract it.

The process of DNA extraction is the first step for many laboratory procedures. Scientists must be able to isolate the DNA from the other unwanted substances of the cell gently enough so that the DNA is not broken up.

For this experiment, an onion was used because of its low starch content, which allows the DNA to be more clearly seen.

The salt shields the negative phosphate ends of DNA, which allows these ends to come closer so that the DNA can precipitate out of a cold alcohol solution. The homogenizing solution causes the cell membrane to break down by dissolving the lipids and proteins of the cell, which disturbs the bonds that hold the cell membrane together.

The homogenizing solution then forms complexes with the lipids and proteins causing them to Dische essay out of the solution.

Dische essay

The Dische test is a test done to identify DNA. The Murexide test a test in which the treatment of a substance, usually urine, with nitric acid and ammonia indicates the presence of uric acid by formation of murexide. Positive results form this test yields Purines form Yellow to Red-Violet.

The Wheeler-Johnson Test is a qualitative test for the pyrimidine bases cytosine and uracil, which produces a green coloration when the sample is treated with bromine water. The addition of barium hydroxide will turn the liquid purple.

The Test for phosphate is used to detect phosphate in the DNA, positive reaction yields yellow precipitate. First, the onions were minced and then weighed to 25g. The onions were minced because by mincing the onions, it increase its surface area that helps make the membrane at the surface easier to dissolve, and also allows for more efficient absorption of heat and solutions.

When in SDS, the proteins and lipids of the membrane, but especially the lipids, are broken down because the SDS causes the bonds holding the membrane together to break. The lipids, which are repelled by the SDS, separate and break up the membrane.

Then the solution together with the onion was heated at 60 degrees, this method was used to speed the breakdown process by energizing the molecules, and also, hopefully help to dissolve the phospholipid bilayer by destroying the proteins and breaking the bonds that hold the phospholipids in place.

By exciting the molecules, the heat might cause the fluid bilayer to break and become a gas-like substance, no longer serving as a barrier for the DNA. The heat softens the membrane as a whole. This entire step, homogenation, is used to free the DNA from its protective barriers.

Then crude papain was added, because Deproteinization which involves adding a protease enzyme Papain will denature the proteins clinging to the DNA making the molecule flexible and easy to spool. Then the solution was then heated again to 60 degrees for 10 minutes with occasional stirring.

Then it was placed in an ice bath, this is because by cooling the solution, it will help prevent denaturation, which might destroy the DNA if it was exposed to prolonged heating. After putting it in an ice bath, the solution was then placed in a blender and was blended for 45 seconds, after.

This was done because the procedure also frees the DNA from another protective barrier, the thick cell wall that all plant cells have. The blending should cause many of the cell walls, containing cellulose, to break, and therefore leave the DNA in the cytoplasm, and no protective thick cellulose wall blocking the cytoplasm from its external environment.

We did not need to do this to the bacteria because it does not have a cell wall. The blended solution was then filtered through 4 layers of cheesecloth leaving the foam untouched.

This is because it leaves behind thicker materials, including any parts of the remaining onion itself. All waste not needed for the experiment is filtered out, such as cellulose of the cell walls, pectins, and excess tissues like the skin sclerenchyma cells of the onion. The analysis of this was that the DNA is polar, but the reaction with the ethanol makes the DNA nonpolar, and therefore resistant to the homogenizing medium that it is in.

The DNA forms its own layer, a precipitate between the liquid ethanol and liquid homogenate.Extraction of DNA from onions Essay Sample. The intent of the experiment was to see firsthand the isolation of DNA organize a works tissue without destructing its construction and sequence - Extraction of DNA from onions Essay Sample introduction.

A white onion was used for the experiment. Irene Dische (born February 13, ) is an American-German author and journalist who has written several international bestsellers.

Biography. Daughter to Jewish refugees, scientist Zacharias Dische and Nationality: United States. Essay on Diarrhea: What are its causes, symptoms and prevention?

Kapil Saini Here you can publish your research papers, essays, letters, stories, poetries, biographies, notes, reviews, advises and allied information with a single vision to liberate knowledge. ISOLATION OF DNA AND DISCHE TEST Ramos ME, Ricohermoso JJ, Roquid PMR, Rosales J, Salvatera D Department of Biological Sciences College of Science, University of Santo Tomas Manila, Philippines Isolation of DNA is an important molecular process used for determining the physical properties of DNA.

A white onion was used for the experiment. After several procedures. Deoxyribonucleic acid isolate was the seeable consequence. Different chemical trials were performed on the Deoxyribonucleic acid isolate. viz.: Dische Test. Murexide Test.

Wheeler-Johnson trial and Test for . However, your essay is unlikely to compensate for grades and test scores that are too far below average, since, first and foremost, the primary bases for evaluation are the quantitative aspects of your application.

Extraction of DNA from onions | Essay Example