1. This document outlines the objectives for reviewing the genetics of bacteria and viruses. It includes topics such as the history of virus discovery, viral structure and life cycles, viral transmission, and the genetics of bacteria including DNA structure, gene regulation, and horizontal gene transfer mechanisms. 2. Specific viruses and bacteria are discussed as examples to illustrate key concepts. Viruses covered include phage T4, phage lambda, herpes viruses, retroviruses, and tumor viruses. The bacterial topics focus on the E. coli lac and trp operons to demonstrate gene regulation and metabolism control. 3. The objectives cover viral and bacterial genetics at both the molecular and applied levels, with topics ranging from viral emergence and disease

1. Chapter 18-The Genetics of Bacteria and
Viruses-Review
Objectives
The Genetics of Viruses
1. Recount the history leading up to the discovery of viruses. Include the
contributions of Adolf Mayer, D. Ivanowsky, Martinus Beijerinck, and Wendell
Stanley.
2. List and describe the structural components of viruses.
3. Explain why viruses are obligate parasites.
4. Distinguish between the lytic and lysogenic reproductive cycles, using phage T4
and phage lambda as examples.
5. Describe the reproductive cycle of an enveloped virus. Explain how the
reproductive cycle of herpes viruses is different.
6. Describe the reproductive cycle of retroviruses.
7. Explain how viral infections in animals cause disease.
8. Define quot;vaccinequot; and describe the research of Jenner that led to the
development of the smallpox vaccine.
9. Describe the best current medical defenses against viruses. Explain how AZT
helps to fight HIV infections.
10. Describe the mechanisms by which new viral diseases emerge.
11. List some viruses that have been implicated in human cancers and explain
how tumor viruses transform cells.
12. Distinguish between the horizontal and vertical routes of viral transmission in
plants.
13. Describe the structures and replication cycles of viroids and prions.
14. List some characteristics that viruses share with living organisms and explain
why viruses do not fit our usual definition of life.
15. Describe the evidence that viruses probably evolved from fragments of
cellular nucleic acid.

2. The Genetics of Bacteria
16. Describe the structure of a bacterial chromosome.
17. Describe the process of binary fission in bacteria.
18. Compare the sources of genetic variation in bacteria and humans.
19. Compare the processes of transformation, transduction, and conjugation.
20. Distinguish between plasmids and viruses. Define an episome.
21. Explain how the F plasmid controls conjugation in bacteria.
22. Describe the significance of R plasmids. Explain how the widespread use of
antibiotics contributes to R-plasmid-related disease.
23. Define transposon and describe two types of transposition.
24. Distinguish between an insertion sequence and a complex transposon.
25. Describe the role of transposase and DNA polymerase in the process of
transposition.
26. Briefly describe two main strategies that cells use to control metabolism.
27. Explain the adaptive advantage of genes grouped into an operon.
28. Using the trp operon as an example, explain the concept of an operon and the
function of the operator, repressor, and co-repressor.
29. Distinguish between structural and regulatory genes.
30. Describe how the lac operon functions and explain the role of the inducer,
allolactose.
31. Explain how repressible and inducible enzymes differ and how those
differences reflect differences in the pathways they control.
32. Distinguish between positive and negative control and give examples of each
from the lac operon.
33. Explain how cyclic AMP and the cyclic AMP receptor protein are affected by
glucose concentration.