Download BIOL 191 Introductory Microbiology

BIOL 191 Introductory Microbiology
Chap. 13 Viruses, Viroids and Prions Outline
I.
General Characterisitcs of Viruses
SLIDE 1
a. Intro
i. Table 13.1 p. 368 Comparing Viruses and Bacteria
ii. *Obligatory*intracellular*parasites*: What does this
mean?
iii. Define virus
b. Host Range. What does the host *range* depend on? What is
a bacteriophage?
c. Viral Sizes Fig. 13.1 p. 369
II.
Viral Structure -
Define ‘Virion’
SLIDE 2
a. Nucleic Acid –
i. Genetics
1. Chap. 8 pp. 211-212, Fig. 8.2 p. 213 The Flow of
Genetic Information
ii. Clinical Focus pp. 370-371 Influenza Virus A
iii. What types of nucleic acids may viruses have? See Table
13.2 p. 375-376
b. Capsid and Envelope
i. Spikes
1. H (Hemagglutinin) proteins1
2. N (Neuraminidase) proteins2
1 Hemagglutinin is one of two virally-coded integral envelope proteins of the influenza virus.
Hemagglutinin is responsible for host cell binding and subsequent fusion of viral and host
membranes after the virus has been taken up. In the first step of infection it binds to receptor
proteins on target cell surfaces and later promotes the release of the flu virus into the host
cytoplasm. http://www.callutheran.edu/BioDev/omm/jmol/ha/ha.html#intro
2 Projections from surfaces of influenza viruses containing neuraminidase are involved in the
release of viruses from infected cells.
Mosby's Medical Dictionary, 8th edition. © 2009, Elsevier.
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c. General Morphology
III.
SLIDES 3-6
Taxonomy of Viruses
a. What is ‘taxonomy’?
b. How does the International Committee on Taxonomy of
Viruses group viruses?
c. What is a viral species?
IV. Isolation, Cultivation and Identification of Viruses
a. How are bacterial and animal viruses grown in the lab?
SLIDES 7, 8
b. What are some ways viruses are identified? SLIDES 9, 10
V. Viral Multiplication
Chap. 8 Microbial Genetics: Using your textbook, in Chap. 8, be sure you know what
mRNA, tRNA, and rRNA refer to
What genes do viruses have? What enzymes do virions contain?
A. Multiplication of Bacteriophages
a. T-Even Bacteriophage Lytic Cycle
i. Fig. 13.11 The lytic cycle of a T-even bacteriphage p.
381 SLIDES 11, 12
ii. Know the steps of the lytic life cycle
1. Attachment
2. Penetration
3. Biosynthesis
4. Maturation
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5. Release
iii. Know general info about the T-even bacteriophages
iv. Know all bolded words and how they relate to the
topic
b. Bacteriphage Lambda Lysogenic Cycle (temperate phages)
i. Know the steps and alternatives of the lysogenic
cycle
1. Fig. 13. 12 The lysogenic cycle of
bacteriophage lambda in E. coli SLIDE 13
2. Attachment
3. Phage DNA circularization
a. Lytic
b. Lysogenic
i. Prophage formation
ii. What happens when the
bacterium reproduces?
iii. Can lysogenic viruses be lytic?
ii. What are important possible results of lysogeny?
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Chap. 8 Fig. 8.28 p. 239 Generalized transduction, in
which any bacterial DNA can be transferred from one
cell to another.
Fig. 13.13 p. 383 Specialized transduction, in which only
DNA on either side of the prophage DNA can be
transferred.
B. Multiplication of Animal Viruses
a. How do animal viruses differ from phages? Table 13.3 p.
384 and text discussion
SLIDE 22
b. Why might some people be resistant to a specific virus but
not others? How is ‘attachment’ related to drug
development against viruses?
c. Know the steps and alternatives of animal virus
multiplication
d. Steps in the animal virus infection process
i.
ii.
iii.
iv.
Attachment
Entry
SLIDES 14, 15
Uncoating
Biosynthesis
1. Biosynthesis of DNA Viruses SLIDE 16
a. Fig. 13.15 Foundation Fig. Replication of
a DNA-Containing Animal Virus
b. Know text discussion of the Families
Herpesviridae and Papovaviridae
2. Biosynthesis of RNA Viruses SLIDES 17-20
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a. Fig. 13.17 p. 388 Pathways of
multiplication used by various RNAcontaining viruses
b. Know text discussion of Retroviridae
v. Maturation and Release
1. Cell Rupture
2. Budding
SLIDE 21
C. Compare Bacteriophage and Animal Virus Multiplication
SLIDE 22
Table 13.3 p. 384
D. Comparison of DNA & RNA Viruses
SLIDE 23
Table 13. 4p. 385
VI. Viruses and Cancer
A. Define oncogenes, oncogenic viruses (oncoviruses),
Transformation, Transformed cells
B. What % of cancers is known to be virus-induced?
C. DNA and RNA Oncogenic Viruses: Know examples from the text
discussion
VII. Latent Viral Infections: Define and know examples from text discussion
Fig. 13.21 p. 392 Latent and persistent viral infections
VIII. Prions
See Fig. 13.22 p. 393 How a protein can be infectious
A. Know examples and how they are different from viruses
B. Nervous System Diseases caused by Prions Chap. 22 p. 629-632
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IX. Plant Viruses and Viroids
A. Know general info
B. Why are plants somewhat protected against many diseases?
C. Define viroid
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