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MYCOLOGY AND VIROLOGY > Basic Virology > Flashcards

Basic Virology Flashcards

(72 cards)

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1
Q

Virus

A

Slimy liquid poison; substance produce by the body as tge result of disease, especially one that capable of infecting others

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2
Q

Viruses may have arisen from:

A
  1. Mobile genetic elements that gain the ability to move between cells
  2. May be descendats of previously living organisms
  3. Derived from DNA or RNA nucleic acid of host cells that become able to replicate autonomously and evolve independently
  4. Degenerate formd of intracellular parasites
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3
Q

Showed that a disease im tobacco was caused by a virus

A

1890, Ivanovski and Beijerinck

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4
Q

Discovered an animal virus that causes foot and mouth disease in cattle

A

1890, Loeffler and Frosch

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5
Q

Viruses that infected a bacterium

A

Bacteriohage or phages * They are needed for transduction

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6
Q

Viral growth cycle

A

*Viruses cannot replicate on their own

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7
Q

The period between the infection and the appearance of a matured virus in the cell *Virion

A

Eclipse period

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8
Q

Composed of regular, repeating subunits that gives rise to its crystalline appearance. Contain only those parts that it needed to invade and control host cell

A

Molecular structure

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9
Q

External coating

A

Capsid *Envelope- in 13 of the 20 families of animal viruses

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10
Q

no envelope

A

Naked virus

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11
Q

core

A

DNA (double stranded)
RNA (single stranded)

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12
Q

capsid + nucleic acid

A

Nucleocapsid

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13
Q

fully formed virus that can establish an infection in a host cell

A

Virion

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14
Q

Capsid is constructed from identical subunits called?

A

capsomers

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15
Q

types of capsid

A

Helical, Icosahedral, Complex

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16
Q

take a bit of the host cell membrane to form an envelope

A

enveloped viruses

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17
Q

In the envelope, some or all of the regular membrane proteins are replaced with

A

viral proteins

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18
Q

Some proteins form a___________ between the envelope and the capsid

A

binding layer

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19
Q

Glycoproteins remain exposed as spikes; essential for attachment

A

peplomers

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20
Q

Functions of the Viral Capsid/Envelope

A
  • Protect nucleic acids.
  • Help introduce the viral DNA or RNA into a suitable host cell.
  • Stimulate the immune system to produce antibodies that can protect the host cells against future infections.
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21
Q

at the core of the virus

A

Nucleic acid

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22
Q

the sum total of the genetic information carried by an organism

A

genome

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23
Q

exceptions to the rule

A

Parvoviruses contain single-stranded DNA

Reoviruses contain double-stranded RNA

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24
Q

DNA viruses

A
  • ssDNA
  • dsDNA
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25
dsDNA
Linear, and circular
26
genomes that are ready for immediate translation into proteins
positive-sense RNA
27
genomes have to be converted into the proper form to be made into proteins
Negative-sense RNA
28
individual genes exist on separate pieces of RNA
segmented
29
the gold standard in the identification
molecular methods; genetic sequencing
30
OTHER SUBSTANCES IN THE VIRUS PARTICLE - ENZYME
for specific operations within the host cell
31
OTHER SUBSTANCES IN THE VIRUS PARTICLE POLYMERASES
to synthesize DNA and RNA
32
OTHER SUBSTANCES IN THE VIRUS PARTICLE REPLICASES
to copy RNA
33
1. Structure 2. Chemical composition 3. Similarities in genetic makeup
MAIN CRITERIA
34
International Committee on the Taxonomy of Viruses, 2000
3 orders 63 families “-viridae” 263 genera “-virus”
35
7 GROUPS IN BALTIMORE'S CLASSIFICATION
1. Double stranded DNA viruses 2. Single stranded DNA viruses 3. Double stranded RNA viruses 4. Positive sense single stranded RNA viruses 5. Negative sense single stranded RNA viruses 6. Single stranded reverse transcribing RNA viruses 7. Double stranded reverse transcribing DNA viruses
36
I, II, VII
DNA viruses
37
ENVELOPED VIRUSES
Poxviridae (complex) – linear Herpesviridae – linear, icosahedral, toroid Hepadnaviridae – circular
38
NONENVELOPED dsDNA
Adenoviridae – linear, icosahedral Papovaviridae – circular, icosahedral
39
NONENVELOPED ssDNA
Parvoviridae
40
* Virus encounters susceptible host cells * Adsorbs specifically to receptor sites on the cell membrane Because of the exact fit required, viruses have a limited host range
ADSORPTION
41
Exact fit:
Exact fit: Lock and key model or goodness of fit model
42
* Flexible cell membrane of the host is penetrated by the whole virus or its nucleic acid * Endocytosis: entire virus engulfed by the cell and enclosed in a vacuole or vesicle * The viral envelope can also directly fuse with the host cell membrane
PENETRATION
43
* Enzymes in the vacuole dissolve the envelope and capsid * The virus is now uncoated
UNCOATING
44
Free viral nucleic acid exerts control over the host’s synthetic and metabolic machinery
SYNTHESIS
45
SYNTHESIS AND REPLICATION OF DNA VIRUSES
NUCLEUS DNA enters the nucleus and is transcribed into RNA The RNA becomes a message for synthesizing viral proteins (translation) New DNA is synthesized using host nucleotides
46
SYNTHESIS AND REPLICATION OF RNA VIRUSES
CYTOPLASM
47
Mature virus particles are constructed from the growing pool of parts
ASSEMBLY
48
RELEASE! Nonenveloped and complex viruses are released when ?
the cell lyses or ruptures
49
Enveloped viruses are liberated by?
EXOCYTOSIS OR BUDDING
50
HOW MANY VIRIONS MAY BE RELASED?
3,000 TO 100,000
51
ENTIRE LENGTH OF CYCLE
8-36 HOURS
52
DAMAGE TO THE HOST CELL AND PERSISTENT INFECTIONS virus-induced damage to the cell that alters its microscopic appearance
CYTOPATHIC EFFECTS
53
compacted masses of viruses or damaged cell organelles
INCLUSION BODIES
54
Response in Animal Cell
Virus
55
Cells round up; inclusions appear in cytoplasm
Smallpox virus
56
Cells fuse to form multinucleated syncytia; nuclear inclusions
Herpes simplex
57
Clumping of cells; nuclear inclusions
ADENOVIRUS
58
Cell lysis; no inclusions
POLIOVIRUS
59
Cell enlargement; vacuoles and inclusions in cytoplasm
REOVIRUS
60
Cells round up; no inclusions
INFLUENZA VIRUS
61
No change in cell shape; cytoplasmic inclusions (Negri bodies)
RABIES VIRUS
62
Syncytia form (multinucleate)
Measles virus
63
Some viral infections maintain a _________ wherein the cell harbors the virus and is not immediately lysed
CARRIER RELATIONSHIP
64
from a few weeks to remainder of the host's life
PERSISTENT INFECTIONS SLOW VIRUSES
65
Some viruses remain in __________, periodically becoming activated
a chronic latent state Herpes viruses and Varicella-Zoster virus (VZV)
66
Some viruses enter their host cell and _______ its genetic material, leading to cancer
PERMANENTLY ALTER Oncogenic viruses Their effect is called transformation
67
mammalian viruses capable of initiating tumors
ONCOVIRUSES
68
VIRUSES THAT INFECT BACTERIA
* Bacteriophages * Most contain dsDNA * Often make the bacteria they infect more pathogenic for humans
69
* Icosahedral capsid head containing DNA * Central tube surrounded by a sheath * Collar * Base plate * Tail pins * Fibers
T-EVEN PHAGES
70
special DNA phages that undergo adsorption and penetration but are not replicated or released immediately Instead, the viral DNA enters an inactive _________
TEMPERATE PHAGES ; PROPHAGE STAGE
71
the cell’s progeny will also have the temperate phage DNA
Lysogeny
72
when a bacterium acquires a new trait from its temperate phage
LYSOGENIC CONVERSION

MYCOLOGY AND VIROLOGY (1 decks)

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