Biology 2
CHAPTER 17 Objectives
MICROBIAL MODELS: THE GENETICS OF VIRUSES AND BACTERIA
OBJECTIVES:
1. Recount the history leading up to the discovery of viruses and include the contributions of A. Mayer, D. Ivanowsky, Martinus Beijerinck and Wendell Stanley.
2. List and describe structural components of viruses.
3. Explain why viruses are obligate parasites.
4. Describe three patterns of viral genome replication.
5. Explain the role of reverse transcriptase in retroviruses.
6. Describe how viruses recognize host cells.
7. Distinguish between lytic and lysogenic reproductive cycles using phage T4 and phage l as examples.
8. Outline the procedure for measuring phage concentration in a liquid medium.
9. Describe several defenses bacteria have against phage infection.
10. Using viruses with envelopes and RNA viruses as examples, describe variations un replication cycles of animal viruses.
11. Explain how viruses may cause disease symptoms and describe some medical weapons used to fight viral infections.
12. List some viruses that have been implicated in human cancers and explain how tumoe viruses transform cells.
13. Distinguish between horizontal and vertical routes of viral transmission in plants.
14. List some characteristics that viruses share with living organisms and explain why viruses do not fit or usual definition of life.
15. Provide evidence that viruses probably evolved from fragments of cellular nucleic acid.
16. Describe the structure of a bacterial chromosome.
17. Describe the process of binary fission in bacteria and explain why replication of the bacterial chromosome is considered to be semi conservative.
18. List and describe the three natural processes of genetic recombination in bacteria.
19. Distinguish between general transduction and specialized transduction.
20. Explain how the F plasmid controls conjugation in bacteria.
21. Explain how bacterial conjugation differs fro, sexual reproduction in eucharistic organisms.
22. For donor and recipients bacterial cells, predict the consequences of conjugation between an F+ and F- cell; Hfr and F- cell.
23. Explain how a geneticist can use several features of conjugation to roughly map a bacterial chromosome.
24. Define transpoon and describe two essential types of nucleotide sequences found in transposon DNA.
25. Distinguish between an insertion sequence and a complex transposon.
26. Describe the role of transposes and DNA polymerase in the process of transposition.
27. Explain how transposons can generate genetic diversity.
28. Briefly describe two main strategies cells use to control metabolism.
29. Explain why grouping genes into an operon can be advantageous.
30. Using the trp operon as an example, explain the concept of an operon and the function of the operator, repressor and co repressor.
31. Distinguish between structural and regulatory genes.
32. Describe how the lac operon functions and explain the role of the inducer, allolactose.
33. Explain how repressible and inducible enzymes differ and how these differences reflect differences in the pathways they control.
34. Distinguish between positive and negative control, and give examples of each from the lac operon.
35. Explain how cap IS AFFECTED BY GLUCOSE CONCENTRATION.
36. Describe how E. coli uses the negative and positive controls of the lac operon to economize on RNA and protein synthesis.