Part 1: Introduction
DNA is a long, double-stranded helix nucleic acid contained in the nucleus of all animal cells. Its purpose is to store all the genetic information of the organism. DNA is comprised of nucleotides, which are simple molecules formed by 3 substances: a sugar (ribose or deoxyribose), a phosphate, and 1 of 4 nitrogenous bases (adenine, thymene, cytosene, guanine.) These bases are what code the genetic information used to determine almost all of the organism's characteristics. The correct formation and function of DNA is incredibly important for any organism, as a flaw can prove deadly. Genetic disfunctions can kill an organism before it has time to develop.
In this lab, we will be precipitating our own DNA. Precipitating DNA can be used by scientists and chemists to research genetics, practice cloning, test for traits or the probability of developing diseases, and also match DNA for forensics.
First we chew our cheeks to loosen cheek cells, then we swish around salene solution in our mouths. Then we spit the solution in a test tube. Next we add lysis buffer, which is a detergent, which breaks open the cell and nuclear membranes. This is required to access the DNA. Next we add protease, an enzyme that breaks down proteins. This is used because DNA is wrapped around proteins called histones, which let the DNA coil many, many times to reduce its size drastically. Removing these histones makes the DNA form into one large thread. The protease also breaks down unwanted molecules, like mitochondria, endoplasmic reticulum, and the golgi apparatus. Protease also destroys DNase, which is an enzyme that destroys DNA. If we want to collect the DNA, we want it to not be destroyed. Next we put the test tube in a water bath at 50 degrees Celcius, which catalyzes the reaction, mainly by helping the lysis buffer. Also many other bacteria will be killed at this temperature, and the growth of E. coli was slowed drastically.
Next we add cold ethanol, which cools the solution, which speeds the precipitation of DNA. After giving the DNA a few minutes to precipitate, we extract it from the solution with a pipette. We then put the DNA in a small container that is also a necklace piece, so we can have our own DNA in a super cool necklace.
