The Genetics of Viruses

1.

Recount the history leading up to the discovery of viruses. Include the contributions of Adolf Mayer, Dimitri Ivanowsky, Martinus Beijerinck, and Wendell Stanley.

2.

List and describe the structural components of viruses.

3.

Explain why viruses are obligate intracellular parasites.

4.

Explain how a virus identifies its host cell.

5.

Describe bacterial defenses against phages.

6.

Distinguish between the lytic and lysogenic reproductive cycles, using phage lambda as an example.

7.

Describe the reproductive cycle of an enveloped virus. Explain the reproductive cycle of the herpesvirus.

8.

Describe the reproductive cycle of retroviruses.

9.

List some characteristics that viruses share with living organisms and explain why viruses do not fit our usual definition of life.

10.

Describe the evidence that viruses probably evolved from fragments of cellular nucleic acids.

11.

Define and describe mobile genetic elements.

12.

Explain how viral infections in animals cause disease.

13.

Describe the best current medical defenses against viruses. Explain how AZT helps to fight HIV infections.

14.

Describe the mechanisms by which new viral diseases emerge.

15.

Distinguish between the horizontal and vertical routes of viral transmission in plants.

16.

Describe viroids and prions.

17.

Explain how a non-replicating protein can act as a transmissible pathogen.

The Genetics of Bacteria

18.

Describe the structure of a bacterial chromosome.

19.

Compare the sources of genetic variation in bacteria and humans.

20.

Compare the processes of transformation, transduction, and conjugation.

21.

Distinguish between generalized and specialized transduction.

22.

Define an episome. Explain why a plasmid can be an episome.

23.

Explain how the F plasmid controls conjugation in bacteria.

24.

Describe the significance of R plasmids. Explain how the widespread use of antibiotics contributes to R plasmid-related disease.

25.

Explain how transposable elements may cause recombination of bacterial DNA.

26.

Distinguish between an insertion sequence and a transposon.

27.

Describe the role of transposase in the process of transposition.

28.

Briefly describe two main strategies that cells use to control metabolism.

29.

Explain the adaptive advantage of genes grouped into an operon.

30.

Using the trp operon as an example, explain the concept of an operon and the function of the operator, repressor, and corepressor.

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 those 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 cyclic AMP and catabolite activator protein are affected by glucose concentration.