AP Biology
Chapter 18 Guided Reading Assignment
Name _________________________
1.
How and what did Dr. Mayer discover specifically in 1883?
2.
What did Ivanowsky conclude that built on Mayer’s work?
3.
What logic did Beijerinck use to lead to the idea of a virus?
4.
How was the existence of a virus finally confirmed and by whom?
5.
How small are viruses?
6.
Label the parts of these two viruses.
7.
What kind of nucleic acids are the viral genomes
made of?
10. What are viral envelopes and what is their
function?
8.
What is the name for a protein shell enclosing the
viral genome?
11. Where are the most complex capsids found?
9.
What are the subunits of capsids?
12. Define host range.
13. List the steps of the simplified viral reproductive cycle.
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14. What is the phage reproductive cycle that culminates in the death of the host cell?
15. What kind of phage only reproduces by a lytic cycle?
16. How do bacteria defend themselves against phages?
17. Label the steps of the lytic cycle of a T4 phage?
18. What is the phage reproductive cycle that replicates the phage genome without destroying the host?
19. What are phages called that are capable of using both modes of reproduction?
20. What is a prophage?
21. What is an example of the interaction between a prophage and a bacterium?
22. What is the use of a viral envelope in animal viruses?
23. Does this reproductive cycle kill the host cell?
24. What are retroviruses and how do they use reverse transcriptase?
25. Label the parts of HIV.
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26. HIV is an RNA virus that uses an envelope as well as being a retrovirus. Compare and contrast HIV and an
enveloped RNA virus that is not a retrovirus.
HIV
BOTH
Enveloped/RNA
27. Is it believed that viruses evolved before or after the first cells appeared and what evidence is used to support the idea?
28. What are vaccines?
29. What are the three processes that contribute to the emergence of viral diseases?
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30. Compare and contrast animal viruses with plant viruses.
Animal Viruses
BOTH
Plant Viruses
31. List and explain the two major routes along which plant viruses spread.
32. Name and describe the two simplest infectious agents.
33. Why does the long incubation period of prions increase their danger as a cause of human disease?
34. What is the main component of most bacterial genomes?
35. How is the DNA arranged in the nucleoid region of the bacterial genome?
36. What is a plasmid?
37. Describe the process of binary fission.
38. Why do mutations make such a large contribution to bacterial genetic variation as compared to humans?
39. Distinguish between the three mechanisms of transferring DNA from one bacterial cell to another that results in
increased genetic diversity.
40. What generally must be present for the sex pili to donate DNA during conjugation?
41. What is special about the F plasmid?
42. What is an episome?
43. What are R plasmids and why are these a problem to humans?
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44. How does this relate to natural selection?
45. Define transposable elements.
46. Do transposable elements exist independently?
47. What is a common name for transposable elements?
48. What is the name for the simplest transposable
elements?
49. What is the name for transposable elements that are
longer and more complex than insertion sequences?
50. What is an example of the benefit to bacteria of these
transposable elements?
51. What are the two ways that metabolic control can occur within bacteria?
52. What is the key advantage of grouping genes of related function in to one transcription unit?
53. What is this “switch” called?
54. Where is an operator positioned?
55. What does the operator control?
56. What is the name for the operator, promoter, and the genes
they control?
57. Label the parts of the trp operon.
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58. What can happen if the trp operon is turned “on”?
63. How is the trp repressor protein and allosteric
protein?
59. What turns the “switch” off?
64. Define corepressor.
60. How does a repressor work?
65. What are the two methods of negative gene
regulation?
61. What gene controls the making of the trp
repressor protein?
66. Why is the trp operon considered repressible?
62. What are the two states that the operator
switches between?
67. What is the definition of an inducible operon?
68. Label the lac operon.
69. What does the inducer do?
70. Why are repressible enzymes generally associated with anabolic pathways and how is this an advantage to the
organism?
71. How does positive gene regulation work?
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