Mindanao State University
General Santos City
Bio 108: Cell Biology
Laboratory Report
August 28, 2013
DNA Extraction on Onion (Allium cepa) and Human Cheek Cell
Arriza, Rolland Merch
Buscato, Carl G.
Butil, Conrad G.
Leonida, Renee Theresa
ABSTRACT
This activity observes the DNA present in onion (Allium cepa) and human cheek cells by extracting it with the addition of lysis buffer and chilled ethanol. The lysis buffer is prepared from squeezed onion mixed with salt and Pantene Pro-V Shampoo. The buffer degrades the protein enveloping the DNA found in onion and cheek cells Cheek cells are obtained from gargled gatorade. Extracts are then filtered and subjected to addition of chilled ethanol. DNA is insoluble in alcohol making it to precipitate, DNA is then extracted.
Keywords: DNA extraction, onion, human cheek cell, lysis
INTRODUCTION
DNA Extraction is the removal of deoxyribonucleic acid (DNA) from the cells or viruses in which it normally resides. Extraction of DNA is often an early step in many diagnostic processes used to detect bacteria and viruses in the environment as well as diagnosing disease and genetic disorders. The process of isolating DNA from a cell is the first step for many laboratory procedures in biotechnology. The scientist must be able to separate the DNA from the unwanted substances of the cell gently enough so that the DNA is not broken up or shredded. The procedure you will be doing is a modification of the "Marmur" preparation which is used worldwide in biotechnology laboratories.
A "Filtrate" is made of onions treated with salt, distilled water and detergent(SDS). An onion is used because it has a low starch content which allows the DNA to be seen more clearly. The salt shields the negative phosphate end of DNA which allows these ends to come closer so they can precipitate out of a cold alcohol solution. The detergent causes the cell membrane to breakdown by
References: http://www.invitrogen.com/site/us/en/home/Products-and-Services/Applications/DNA-RNA-Purification-Analysis/dna-extraction/genomic-dna-extraction/plant-dna-extraction.html http://www.accessexcellence.org/AE/AEC/AEF/1994/dollard_onionDNA.php