DNA Precipitation: The Human Wonder

       DNA is the genetic code our body that is located in each cell in our body and decides everything about us. DNA is a chain of nucleotides with the bases Adinine, Guanine, Cytosine, and Thinine. DNA is the "manual book" for our cells. It tells our cells how to make certain proteins. DNA does this by sending the code to ribosomes which then make the proteins based the code. DNA precipitation is a method used to concentrate/isolate DNA from a cell. To achieve this we have to break down the cell membrane and the nuclear membrane. Then we have to add certain ingrediants to be able to actually see the DNA with the naked eye. This is used in the real world as well. Researchers can use this method to isolate DNA and then take samples of it and learn more about it. They can use the info gained to test for certain traits and dieseases. In order to make this happen we have to add certain ingrediants and do certain things. First we have to loosen our cheek cells and put it in saline which is isotonic and the same salt concentration as our bodies. Then we add the lysis buffer which breaks down the cellular and nuclear membrane. Then protease which breaks down the DNase in our cells (kills DNA (enzyme for DNA) )  and also breaks down the histone proteins which the DNA is wrapped around. We then put it into a hot bath to speed up the reaction and we add salt which neutralizes the negative charge of DNA. Lastly we add cold ethanol which helps precipitate the DNA.
      In my DNA lab I went through all the steps and got an amazing result. Once I added the ethanol I saw these thin strands of a jello like substance appear. It was really cool and I appreciated the awesomness of DNA after that. Some errors might have occured. We coulded have added to much of a substance like ethanol or salt and that could have affected how much DNA we ended up with after that . Overall I really liked the lab and had a good time doing it.




DNA



Precipitated DNA

Yogurt and bacteria for dummies

       In the 1800s people sickened and died for no apparent cause. Koch's postulates were invented by Robert Koch in order to prove that a certain microbe caused a certain disease. Bacteria are small microbes that are all around us. They are the the most successful form of life on the great planet Earth. Bacteria have no separate place for the nucleus like eukaryote do. Most bacteria are harmless and do not harm humans in any way. There are a small amount of bacteria that can harm you. There are also some bacteria that are actually good for humans and their digestive systems. These bacteria are called probiotics and can be found in yogurt and other foods. Bacteria that form yogurt are anaerobes and they use enzymes to break down milk sugar (lactose) into lactic acid.
      The purpose of this lab is to prove all of Koch's postulates especially postulate 3. Postulate 3 is: Inoculate healthy individual with pure culture of suspected pathogen. The oobjective of the lab is to use yogurt, ampicillin, and e.coli to prove this point. The technique we are using to prove postulate 3 is used all around the world in different ways to create yogurt from milk. Koch's postulates are also used in labs to isolate unknown pathogens.
       In the experiment we have 4 tubes of milk. We add ampicillin to the Yogurt + amp tube. Then we add yogurt to the yogurt + amp tube and another just milk tube. We are doing this to show that the pathogen is a bacteria because ampicillin kills bacteria so if nothing happens to that tube and the other tube becomes yogurt we know it was the bacteria. After all of this we then add e.coli to a tube of milk. We do this to show that introducing bacteria itself can cause the change to yogurt therefore isolating the pathogen.
       When we recieved our tubes back we came up with some expected and unexpected results. The negative tube that was filled with just milk had stayed in liquid for which was to be expected. The E.coli tube had also stayed in liquid form which had also been expected. The tube which had Yogurt + amp had changed into yogurt which wasn't supposed to happen. Also the tube that contained just milk with yogurt had stayed liquidy. I think this occured because of human error. I think that my group miss labeled the tubes with yogurt+amp and yogurt therefore switching them and explaing the unexpected results.

E.Coli

Yogurt

VIDEO:
http://www.youtube.com/watch?v=fKG-6jEwh_0