Most basic of all procedures and involves purification of DNA. An important step within organic extraction is the removal of proteins. Can be done by extracting aqeous solutions of nucleic acids with phenol or chloroform. There are pros and cons when dealing with organic extraction. The pros are it yields relatively pure, high molecular weight DNA. In addition, DNA is double stranded. This means it is good for RFLP and PCR. The cons are it is time consuming and there is the increase risk of contamination. It also involves use of hazardous chemicals.