Lecture Exam 3 Flashcards
(228 cards)
What is recombinant DNA and genetic engineering?
Purposeful manipulation of genetic material; The insertion deletion, or modification of genes to produce organisms with desired traits
What are the goals of recombinant DNA technology?
Make large quantities of the new DNA, make large quantities of the protein encoded by the genes of interest
What materials and techniques are used in recombinant DNA technology?
endonucleases,
What is the function of each material and technique used in recombinant DNA technology?
How do the materials and techniques used in recombinant DNA technology work?
What are some examples of products produced using recombinant DNA techniques?
Foods, antibiotics like penicillin, vitamins, enzymes found in detergents
What is a gene library?
A series of plasmids, each of which contains a portion of DNA. It exists in bacteria that have been transformed with the mixture of DNA, it can be made using complementary DNA which allows us to only utilize functional DNA and we don’t have to worry about introns.
How are gene libraries made?
They are made by cloning the entire DNA or complementary DNA of an organism. First, you cut the DNA of interest with a restriction enzyme, then you cut the DNA of the vector, using the same restriction enzyme to make compatible ends. After that, you can bind the vectors and genes of interest using ligase, this makes recombinant DNA. Transform bacteria with the mixed recombinants and grow them to make a portion of the library. Each gene is copied to a single clone, and all of the clones collectively make up the gene library.
How does one find the clone of interest?
Replica plating first you make a replica of your master plate on nitro cellulose filter. Then, you will treat the filter with detergent to lose the bacteria. Next, you will treat the filter with sodium hydroxide to separate DNA into single strands. Then you will add radioactively labeled probes, the probes will hybridize with the desired gene from the bacterial cells. Next, wash the filter to remove unbound probes, and expose the filter to x-ray film. Lastly, compare the developed film with the replica of the master plate to identify colonies containing the gene of interest.
What is gel electrophoresis?
A physical separation of DNA fragments by size, with the use of agarose gel, and an electrical current, allowing them to be studied further
How does gel electrophoresis work?
DNA is placed in agarose gel and at each end of the plate negative and positive currents are added. This allows the DNA, which has a net negative charge, to move across the agarose gel towards the positive charge. The large DNA fragments will migrate slower than the smaller fragments. You can also add Ethidium bromide, which is an Intercalating agent, to stain the DNA and allows it to glow when exposed to UV light. This allows for visualization of the DNA fragments following gel electrophoresis.
What is southern blotting?
It is utilized after gel electrophoresis as a way to visualize the DNA. DNA bands are transferred to a nitrocellulose filter through blotting.
How is southern blotting done?
The solution passes through the gel and filter to the paper towels. This produces a nitro cellulose filter with DNA fragments positioned exactly is on the gel. The filter is been exposed to a radioactively labeled probe for a specific gene and the Pro bowl, base pair or hybridize with a short sequence present on the gene. The filter is that exposed to x-ray film, and the fragment containing the gene of interest is identified by a band on the developed film.
What are some of the uses of southern blotting?
DNA fingerprinting,
What is PCR?
It is the production of a large number of identical molecules of DNA in vitro
How does PCR work?
It is a repetitive process consisting of three steps. First, denaturation using heat at 94 C for 1 min, second priming (dNTPs and Taq DNA polymerase) or annealing (stick to complementary DNA) third extension. This process can be automated by using a thermocycler. They will replicate exponentially.
What are some of the uses of PCR?
Epidemiologists use PCR to amplify the genome of an unknown pathogen, for example west Nile virus. It is also used to analyze, ancient DNA, for example, from Neanderthals. It is used forensically to amplify DNA found in blood semen or tissue samples. It is used to determine paternity from tissue or blood samples between two individuals believed to be related.
What is RT PCR?
Reverse transcriptase polymerase chain reaction. It is taking a sample of RNA and using that to make a complementary DNA and then using the complementary DNA to amplify through PCR.
Why would you use RT PCR?
This is used with viruses that have RNA and not DNA, monitor gene expression, diagnose infection, genetic screening
What are DNA microarrays?
Using RT PCR to build a gene test to show which genes are active and inactive.
How are DNA microarrays made?
Probes are prepared by taking complementary DNA that is normal and complementary DNA that is not for example, from a tumor then reverse transcriptase PCR is done, and each type of complementary DNA is labeled with fluorescent dye. You then combine equal amounts of the normal and tumor, complementary, DNA, and then you hybridize probe to the MicroArray and scan it. The ones that are normal are green. The ones that are from the tumor are red and commonalities between the normal and tumor show up as yellow. This is been studied and compared to understand what the genetic make up is of the tumor and how to best treat it.
What are some of the uses of microarrays?
Monitor gene expression, diagnose disease specifically, genetic screening
How is DNA sequenced?
Why sequence DNA?