CHAPTER III RESULTS AND DISCUSSION3.1 Experiment Results After doing lab experiment about DNA isolation in accordance with theprocedures, we found the data that; on the use of tomatoes as the source ofDNA, DNA that can be isolated were most commonly founded in the filtratecontaining solution of Bu krim detergent. While the filtrate containing Surfdetergent solution, DNA obtained were quite a lot but still less when comparedwith previous treatments. In the filtrate containing Rinso detergent powder,DNA obtained was quite a bit. While the time required for the formation ofDNA at each treatment was varied. For tomatoes as DNA source, the fastesttime where DNA formed was in Bu krim detergent solution. Longest timerequired to isolate DNA of tomatoes was in Surf detergent solution. On the use of pear fruit as DNA sources, most of the DNA obtained fromthe filtrate containing solution of Bu krim, whereas little DNA was found onRinso detergent solution. The time required for the formation of DNA in eachsolution is clearly different. For Bu krim detergent powder, the average timeneeded to form DNA is faster than at the Surf detergent solution. When viewed as a whole, the use of pear fruit as a source of DNAproduces DNA precipitate more than the use of tomatoes as the source of DNA.3.2 Discussion DNA isolation basically can be done by using various sources of DNAwhich can be obtained from animals and plants. DNA obtained in theobservation is in the form of DNA strands which are so fine that looks like a
very soft white mist. Efforts for removing the DNA from the cell were done bydestroying cell wall and cell membrane and the nuclear membrane. The first step is to lyse or break open the cell. This can be done bygrinding a piece of tissue in a blender. Plasma membrane or cell membrane iscomposed of fat and protein molecules. Fat molecule composed of two layers,located at the center of the membrane. The functions of the cell membrane areprotecting the cell contents, which serves to maintain the cell contents and tocontrol molecules traffic. Cell membranes in all organisms can suffer damagecaused by the influence of chemical compounds. Chemical compounds that candamage the membrane or cell wall are lysozyme that can affect the polymericcompound so that cell stiffness can no longer be maintained. In the process ofDNA isolation, detergent serves as a destroyer of the cell membrane. Detergentcontains sodium dodecyl sulphate (SDS), which can remove lipid molecules inthe cell membrane so that the membrane structure will be damaged and lyse thecontents of the cells (Jamilah, 2005). In the cell nucleus, DNA is present in a complex structure calledchromatin. Chromatin is composed of a large number of proteins and nucleicacids known as deoxyribonucleic acid (DNA). Chromosomal protein that bindsto DNA is simply divided into two main classes of chromosomal proteinhistone and non-histone. With the bond between the DNA with the protein, thechromatin is highly soluble in water since histones and non-histone protein issoluble in water. Therefore, the isolation of DNA uses salt in order to separatethe DNA with histones and non-histone proteins as well as concentrating the
DNA. This can be happened because the Na+ ions contained by salt capable offorming a bond with the negative pole of the DNA phosphate bond. When theNa+ ions bind to phosphate, the DNA is assembled. The addition of alcohol to the solution intends to do the precipitationbecause DNA is not soluble in alcohol, so that DNA which has beenaccumulated was able to separate from the solution and formed layers ofidentifiable constituent elements.
DAFTAR PUSTAKAYulia, Floweriza. 2012. DNA buah. http://flowerizayulia.blogspot.com/2012/ 01/laporan-dna-buah.html. Diakses tanggal 28 Oktober 2012.Rasyid, Kharisma Aditya. 2011. STRUKTUR DAN FUNGSI MEMBRAN SEL. http://khaditoya.blog.unsoed.ac.id/2011/10/28/struktur-dan-fungsi- membran-sel/. Diakses tanggal 28 Oktober 2012.DNA extraction. http://en.wikipedia.org/wiki/DNA_extraction. Diakses tanggal 28 Oktober 2012.Unima, Biokimia. 2010. SOAL JAWAB BIOLOGI MOLEKULER. http://biokimiaunima.blogspot.com/2010/11/soal-jawab-biologi- molekuler.html. Diakses tanggal 28 Oktober 2012.Robbie. 2008. http://answers.yahoo.com/question/index?qid=20080710142651 AABl7aB. Diakses tanggal 28 Oktober 2012.