Chapter 20 Reading Quiz

1. Chapter 20 Reading Quiz • Genes from two different sources that are combined result in ____. • Where are “sticky ends” found? • What structures, naturally found in bacteria, cut up foreign DNA? • What is the point of the genetic technology “PCR”? • Organisms whose genomes carry genes from another species are known as _____.

2. 1. Explain how advances in recombinant DNA technology have helped scientists study the eukaryotic genome. • It resulted in the appearance of the biotechnology industry • We can now move genes across the species barrier • The Human Genome Project  transcribe and translate the entire human genome • We hope to improve health and food production 

4. 2. Describe the natural function of restriction enzymes. • They are major tools in recombinant DNA technology • They occur naturally in bacteria where they protect the bacterium against intruding DNA • This protection involves restriction in which foreign DNA is cut into small segments 

6. 3. Describe how restriction enzymes and gel electrophoresis are used to isolate DNA fragments. • Restriction enzymes only recognize short, specific nucleotide sequences called recognition sequences or restriction sites • Gel electrophoresis is used to separate either nucleic acids or proteins based upon molecular size, charge, and other physical properties  characteristic banding 

8. 4. Explain how the creation of sticky ends by restriction enzymes is useful in producing a recombinant DNA molecule. • They are used in the laboratory to join pieces of DNA from different sources (sometimes cells or even different organisms) • These are temporary unions  only held by a few hydrogen bonds 

9. 5. Outline the procedures for producing plasmid and phage vectors. • Isolation of vector and gene-source DNA - bacterial plasmids & foreign DNA with gene of interest 2. Insertion of gene-source DNA into the vector - plasmid DNA cut  mix foreign dNA and plasmids  add DNA ligase to catalyze new covalent bonds • Introduction of cloning vector into bacterial cells - naked DNA added to bacterial culture, plasmid DNA taken up by transformation • Cloning of cells (and foreign DNA) - reproduced and cloned 5. Identification of cell clones carrying the gene of interest (indicators added) 

11. 6. Explain how vectors are used in recombinant DNA technology. • Cloning vector  a DNA molecule that can carry foreign DNA into a cell and replicate there • Most often used: bacterial plasmids and viruses 

12. 7. List and describe the two major sources of genes for cloning. • DNA isolated directly from an organism 2. Complementary DNA made in the lab from mRNA templates 

14. 8. Describe the function of reverse transcriptase in retroviruses and explain how they are useful in recombinant DNA technology. • It is the enzyme that transcribes DNA from an RNA template Viral genomic RNA (reverse transcriptase) Viral DNA • Useful in that we can utilize it’s natural function to incorporate genes of interest 

15. 9. Describe how bacteria can be induced to produce eukaryotic gene products. • Expression vectors allow the synthesis of many eukaryotic proteins in bacterial cells • Expression vectors contain a prokaryotic promoter just upstream of a restriction site where the eukaryotic gene can be inserted • The bacterial host cell recognizes the promoter and proceeds to express the foreign gene that has been linked to it 

16. 10. List some advantages for using yeast in the production of gene products. • Yeast cells are easy to grow as bacteria and they contain plasmids • Some recombinant plasmids combine yeast and bacterial DNA and can replicate in either • Posttranslational modifications required to produce eukaryotic proteins can occur 

17. 11. List and describe four complementary approaches used to map the human genome. • Genetic mapping (linkage)  construct a linkage map with several thousand genetic markers • Physical mapping  ordering the DNA fragments - a map made by cutting the DNA of each chromosome into a number of identifiable fragments • Sequencing DNA  the complete nucleotide sequence of a genome is the ultimate map • PCR amplification  amplify DNA in amounts sufficient for study (polymerase chain reaction) • Chromosome walking  start with a known gene and “walk” along the DNA from that locus 

18. 12. Explain how RFLP analysis and PCR can be applied to the human genome project. • RFLP (restriction fragment length polymorphisms)  differences in restriction fragment length that reflects variations in homologous DNA sequences - used as genetic markers for making linkage maps - are a “genetic fingerprint” • PCR (polymerase chain reaction)  allow any piece of DNA to be quickly amplified (copied) in vitro - produces linkage maps without the need for large family pedigree analysis 

19. 13. Describe how recombinant DNA technology can have medical applications such as diagnosis of genetic disease, development of gene therapy, vaccine production, and development of pharmaceutical products. • Disease  DNA technology to diagnose, early detection, and identification of carriers • Gene therapy  traceable genetic disorders may eventually be correctable = normal genes introduced - many social and ethical questions • Vaccines  produce specific protein molecules which could cause immune response; gene splicing could make vaccine pathogens safer • Pharmaceutical products  make mostly proteins - gene splicing applies to insulin and growth hormone (genetically engineered human insulin) 

20. 14. Describe how gene manipulation has practical applications for agriculture. • Essentially to improve productivity Animals  bovine growth hormone (made by ecoli); enhances milk production and weight gain  cellulase (ecoli) hydrolyzes cellulose making the whole plant good for feed Plants  easier to engineer – can be made from a single cell - helps with herbicide  resists pathogens and insects - enhanced food value 

22. 15. Describe how plant genes can be manipulated using the Ti plasmid carried by Agrobacterium as a vector. • Ti plasmid = tumor-inducing • Agrobacterium is normally pathogenic • turned the plasmid into a useful vector by eliminating its disease-causing ability without interfering with its potential to move genetic materials into infected plants 

23. 16. Explain how foreign DNA may be transferred into monocotyledonous plants. • Electroporation  high voltage jolts of electricity to open temporary pores in the cell membrane; foreign DNA can enter the cells through these pores • DNA particle gun  the DNA gun shoots tiny DNA-coated metal pellets through the cell walls into the cytoplasm, where foreign DNA becomes integrated into the host cell DNA 

24. 17. Describe how recombinant DNA studies and the biotechnology industry are regulated with regards to safety and policy matters. • The processes could create hazardous new pathogens • Regulation begins with the self-monitoring approach - moves on to governments and regulatory agencies which promote potential industrial, medical, and agricultural benefits but ensure that the new products are safe 