DNA Protocol

DNA Protocol

Deoxyribonucleic acid (DNA) is a nucleic acid that contains the genetic instructions used in the development and functioning of all known living organisms and some viruses. The main role of DNA molecules is the long-term storage of information. DNA is often compared to a set of blueprints or a recipe, since it contains the instructions needed to construct other components of cells, such as proteins and RNA molecules.

Base Pairing

Each type of base on one strand forms a bond with just one type of base on the other strand. This is called complementary base pairing. Here, purines form hydrogen bonds to pyrimidines, with A bonding only to T, and C bonding only to G. This arrangement of two nucleotides binding together across the double helix is called a base pair. The double helix is also stabilized by the hydrophobic effect and pi stacking, which are not influenced by the sequence of the DNA.

DNA Extraction

DNA extraction is a routine procedure to collect DNA for subsequent molecular or forensic analysis. There are three basic steps in a DNA extraction:a) Breaking the cells open to expose the DNA within, such as by grinding or sonicating the sample b) Removing membrane lipids by adding a detergent. c) Precipitating the DNA with an alcohol — usually ethanol or isopropanol. Since DNA is insoluble in these alcohols, it will aggregate together, giving a pellet on centrifugation. This step also removes alcohol-soluble salt.