Explain the process how scientists use recombinant DNA technology to produce the drug insulin.?
The classic method for doing this is to insert whatever gene you want into a cloning vector, get that cloning vector into bacteria, grow up the bacteria, then get them to turn on that cloning vector to make lots of the desired gene product--in this case, insulin. This method turns the bacteria into insulin-making factories. 1) First, they isolated and purified the gene that codes for insulin from human tissue. 2) Using the appropriate reagents, they inserted that gene into a small, circular piece of bacterial DNA called a plasmid. That plasmid included an "origin of replication," which means that under the right conditions, that plasmid could be turned on and whatever was inserted into it could be expressed. The plasmid is the cloning vector that I referred to above. 3) They took that plasmid and mixed it with bacteria that had been altered so that they would take up foreign DNA. Those bacteria took up that plasmid. 4) They grew those bacteria to a large number, then they added reagents which caused the insulin-containing plasmid to turn on and start making insulin. 5) After a suitable period of time, they harvested the bacteria, broke them open and used standard biochemical methods to isolate and purify the insulin protein. Insulin was the first human protein to be cloned and expressed this way (i.e. recombinant human insulin)--this was the first commerical recombinant product turned out by the very first biotech company, the Genetech Corporation.
What is the role of salt in DNA extraction?
Salt changes the solubility of DNA, and makes more likely to fall out of solution, especially in combination with ethanol.This is a good link: Ethanol Precipitation of DNA and RNA: How it works - Bitesize Bio
What does ethanol do in DNA extraction?
Ethanol is typically used with a salt for nucleic acid extraction. The positively charged ion (Na+) from the salt interacts with the negatively charged phosphate groups of nucleic acids. However, this interaction is electrostatically blocked by water and the nucleic acids will easily hydrogen bond with water (hence, nucleic acids are soluble in water. Ethanol on the other hand allows the positively charged anion to interact with the negatively charged phosphate groups. This interaction shields the charges of both ions, and now they can no longer hydrogen bond with ethanol molecules. Thus, this salt formation precipitates out of the ethanol solution.In other words, nucleic acids are not soluble in ethanol with a salt, allowing extraction.
List the 4 major types of protein conformations (levels) and describe each.?
By conformations I assume you mean the 4 levels of protein structure?? If so.. There are four levels Primary, Secondary, Tertiary, and Quaternary. Each is characterized by a distinct layout of amino acids which will form the protein. Primary is the most simple. It is just a chain of amino acids held together by either a covalent or peptide bond. Secondary is a step above that is when the polypeptides form hydrogen bonds between each other to form either an alpha helix structure or a beta structure. The alpha helix looks somewhat like DNA and the beta sturcutre can be thought of as beta sheets, just stacks of proteins as if they're paper. The Tertiary Structure is when the protein will get a 3D form by adding more bonds between the polypeptides which will help to determine the purpose of the protein. These bonds can be hydrogen bonds, salt bridges, or even disulfide bonds. Finally Quaternary structures are when a protein can develop multiple subunits. For example it's when the protein goes from being a tertiary structure, to having multiple tertiary structures attached. I hope this helps :)
In DNA gel electrophoresis, what is the purpose of a pH buffer such as TBE buffer?
The electrophoresis buffer serves two purposes. It protects nucleic acids by deactivation of nucleases, enzymes that can digest DNA/RNA. Nuclease are not active at higher pH of TAE buffer, which is around 8. Additionally, EDTA chelates metal ions including those required by nucleases for their activity.Buffers provide ions for the conduction of electric current for the process of electrophoresis. If current is not allowed to be conducted through the buffer solution, then no electrophoresis will take place.