Chapter 20 Biotechnology PDF

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This is a very short lecture on Biotechnology...

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Liam McCollum Chapter 20: Biotechnology 1. The Curriculum framework expects that you are familiar with a technique of modern biotechnology, as well as an example of a product of genetic engineering. 2. Genetic Engineering is the process of manipulating genes and genomes. Biotechnology is the process of manipulating organisms or their components for the purpose of making useful products. 3. Recombinant DNA is DNA that has been artificially made, using DNA from different sources. 4. An example of Recombinant DNA is the introduction of a human gene into an E.coli bacterium. 5. Gene cloning is the process by which scientist can produce multiple copies of specific segments of DNA that they can work with in the lab. 6. Restriction enzymes are used to cut strands of DNA at specific locations (called restriction sites) they come from bacteria. 7. When a DNA molecule is cut by restriction enzymes the result is a set of restriction fragments, which will have at least one single-stranded end, called a sticky end. 8. DNA ligase can join complementary single-stranded pieces of DNA together. 9. A vector purpose is to carry the DNA sequence to be cloned and is often a bacterial plasmid. 10. The purpose of cutting the gene of interest and cutting the cloning vector with the same restriction enzyme is it gives the plasmid and the human gene matching sticky ends. 11. DNA ligase is used to join the 2 piece of DNA together 12. The plasmid is taken up by the bacterium by transformation. 13. You can selected for the cells that have been transformed by linking the gene of interest to an antibiotic resistance gene or a reporter gene such as green fluorescent protein. 14. Nucleic acid hybridization is used if we know at least part of the nucleotide sequences of the gene of interest, we can synthesis a probe complementary to it. If the probe is made radioactive or fluorescent, the probe will be easy to track. 15. A genomic library is a set of thousands of recombinant plasmid clones, each of which has a piece of the original genome being studied. 16. cDNA library is made up of complementary DNA made from mRNA transcribed by reverse transcriptase. This technique rids the gene of introns but may not contain every gene in the organism. 17. PCR (polymerase chain reaction) is used to amplify DNA when the source is impure or scanty (as it would be at a crime scene). Figure 5.15 shows the basic steps of the PCR procedure. 18. The point of heating a DNA sample during PCR is to separate DNA strands (denaturation). 19. In step 2 of PCR (annealing): Cool to allow primers to form hydrogen bonds with ends

of target sequence. 20. In step 3 of PCR (extension): DNA polymerase adds nucleotides to the 3’ end of each primer. 21. 2 22. An electric current is applied to the field. DNA is negatively charged and migrates to the positive electrode. Agarose gel is used as a matrix to separate molecules by size. The gel allows smaller molecules to move more easily than larger fragments of DNA. The DNA must be stained or tagged for visualization. 23. A mixture of DNA molecules, usually fragments produced by restriction enzyme digestion (cutting) or PCR amplification, is separated into bands. Each band contains thousands of molecules of the same length. 24.

Ignore 25-30 25. See page 140, Figure 5.16 for more! 26. Genome-wide studies of gene expression are made possible by the use of DNA

microarray assays. 27. Reverse transcription converts mrna from the tested celles into C DNA 28. mRNA molecules from the cells being tested are isolated and converted to cDNA by reverse transcriptase, then tagged with a fluorescent dye. 29. The cDNA bonds to the ssDNA on the chip, indicating which genes are “on” in the cell (actively producing mRNA). 30. This enables researchers, for example, to see differences in gene expression between breast cancer tumors and non-cancerous breast tissue. 31. Restriction fragment length polymorphisms (RELPs) results from small differences in DNA and can be detected by electrophoresis. The difference in banding patterns after electrophoresis allows for diagnoses of disease or is used to answer paternity and identity questions. 32. In animal cloning the nucleus of an egg is removed and replaced with the diploid nucleus of a body cell, a process termed nuclear transplantation. The ability of a body cell to successfully form a clone decreases with embryonic development and cell differentiation. 33. The major goal of animal cloning is reproduction. The major goal of human cloning is the production of stem cells. 34. A stem cell can both reproduce itself indefinitely and, under the proper conditions, produced other specialized cells. Stem cells have enormous potential for medical applications. 35. Embryonic stem cells are pluripotent which means they are capable of differentiating into many different cell types. The ultimate aim is to use them for the repair of damaged or diseased organs, such as insulin producing pancreatic cells for people with diabetes or certain kinds of brain cells for people with Parkinson’s disease. 36. Practical implications of DNA technologies are: a. Diagnosis of disease b. Gene therapy c. The production of pharmaceuticals d. Forensic applications e. Environmental cleanup f. Agricultural development...