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Micro > CH6 pt 2 > Flashcards

CH6 pt 2 Flashcards

1
Q
  • has only one option: to begin multiplying immediately upon entering its bacterial host, followed by release from the host by lysis
  • destroys the host bacterial cells
A

lytic (virulent) phages

lytic cycle

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2
Q
  • two options: upon entry into the host, they can multiply like virulent phages and lyse the host cell, or they can remain within the host without destroying it
  • viral DNA integrates into bacterial chromosome
A

temperate (avirulent) phages

lysogenic cycle

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3
Q

viral nucleic acid either integrated into the bacterial chromosome or free in the cytoplasm

A

prophage

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4
Q

most bacterio phages are either _____ or ______

A

virulent or avirulent

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5
Q

number of phages produced by lytic and lysogenic cycle

A

lytic- aboout 100

lysogenic- none, bc genome replicates but no virions

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6
Q

The protein coat surrounding the viral genome is called the

A

capsid

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7
Q

Plant viruses can be transmitted

A

by insects, using mechanical abrasives, grafting one plant to another, fungi

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8
Q

Naked animal viruses most often gain access to eukaryotic host cells by

A

endocytosis.

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9
Q

Which diseases are caused by prions?

A

kuru and Creutzfeldt-Jakob Disease in humans, mad cow disease, scrapies in sheep

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10
Q

Which of these is incorrect regarding prions?

they are infectious proteins

they cause incorrect folding of normal proteins

they were first described in the early 1900s

they do not contain nucleic acid

A

they were first described in the early 1900s

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11
Q

Animal viruses have been cultivated in

A
  • tissue cultures (monolayers of animal cells).
  • suitable host animals.
  • embryonated eggs.
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12
Q
  • acellular
  • can be observed with an electron microscope.
  • can exist in an intracellular or extracellular phase
  • replicate only inside host cells.
A

viruses

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13
Q
  • a lytic infection most often yields one to two hundred virions
  • they most often have a dsDNA genome
  • they are most often naked
A

phages

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14
Q

has been associated with a form of liver cancer

A

hepatitis B virus

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15
Q

Viral capsid protein subunits are called

A

protomers

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16
Q

Viral capsids are generally constructed without any outside aid once the subunits have been synthesized

A

self-assembly.

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17
Q

A complete virus particle is called a

A

virion

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18
Q

Many of the enzymes found in virus particles are

A

involved in the replication of viral nucleic acid.

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19
Q

Most enveloped viruses use the host __________ membrane as their envelope source.

A

plasma

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20
Q

Cytopathic effects

A

are observable changes in cells due to viral replication

21
Q

Prions are of significance because they cause infections of

A

domestic animals and humans.

22
Q

Glycoprotein spikes protruding from the outer surface of viral envelopes function as

A

factors that bind to host cells.

23
Q

Viroids are of economic significance because they cause disease in

A

plants

24
Q

In the lysogenic cycle

A

the virus becomes a prophage

25
Q

Virion size ranges from

A

10–400 nm.

26
Q

Two major types of symmetry found in viruses include

A

icosahedral and helical

27
Q

Human cancer causing viruses most often have a ___________ genome.

A

dsDNA

28
Q

Which of the following is/are not true about viral envelopes?

The envelope proteins are virus specific.

They are typical lipid monolayers with embedded viral proteins.

They are typical lipid bilayers with embedded viral proteins.

The envelope lipids are derived from the host.

A

They are typical lipid monolayers with embedded viral proteins.

29
Q

Which of the following is not true of plaques?

they result when viruses are cultured in chicken eggs

they vary is size and appearance based on virus replication rates

they can be used to count and isolate phage

they are clear zones on a lawn of bacteria

A

they result when viruses are cultured in chicken eggs

30
Q

Prions are of significance because they cause infections of

A

domestic animals and humans

31
Q

Bacterial viruses typically infect host cells

A

injecting their nucleic acid in host cell

32
Q

describe the lytic cycle

A

In the lytic cycle, new virus particles are made and released when the host cell lyses. Virulent phages are limited to just the lytic cycle.

33
Q

describe the lysogenic cycle

A
  • The lysogenic cycle allows the genome of the virus to be replicated passively as the host cell’s genome is replicated.
  • Certain environmental factors such as UV light can cause a switch from the lysogenic cycle to the lytic cycle.
34
Q

Eukaryotic viruses can cause microscopic or macroscopic degenerative changes or abnormalities in host cells and in tissues that are distinct from lysis

A

cytopathic effects (CPEs)

35
Q

characteristics of viruses associated with human cancers

A

dsDNA or become it when in the cell (retrovirus)

36
Q

transformed cells have

A

uncontrolled growth, loss of normal function, and move to other sites (malignant)

37
Q

___% of human cancers have a virus link

A

15%

38
Q

how are human cancers associated with implications?

A
  • most are dsDNA
    • Hepatitis B (liver cancer), Herpes 8, HPV (cervical cancer)
  • ssRNA
    • HTLV (rare immunity), Hepatitis C
  • many form a provirus
39
Q

types of animal cultivation with advantages and disadvantages

A

-living animals
A- required for an immune response, virulence studies
D- expensive, labor intensive, contamination
-embryonate chicken egg
A- inoculated aseptically (less contamination)
D- can’t view immune responses
-cell/tissue culture
A- visible effects of virus on cells, no contamination
D- not cheap and can’t view immune responses

40
Q

how has virology advanced

A

e- microscopes and cell culture

41
Q

types of cultivation of plant viruses

A

whole plants and plant tissue culture

42
Q
  • vectors
  • mechanical inoculation- carborundum (rub leave with abrasive)
  • grafting- diseased plant onto healthy plant (natural inoculation
A

cultivation of a plant viruses in a whole plant

43
Q

cultivation of bacteriophage

A
  • find them where their host is found
  • young actively growing bacteria culture
    • solid media- plaques, used to count viruses, isolate and purify a virus
    • broth- turbid broth becomes clear
44
Q

clear zones- form from on a lawn of bacteria

A

plaques

45
Q
  • cause plant diseases

- ssRNA with no protein coat

A

viroids

46
Q

interfere with mRNA processing and slicing of mRNA

A

viroid pathogenicity

47
Q
  • incorrectly folded proteinaceous infectious particles (no DNA or RNA)
  • cause transmissible , slow progressing CNS disease
A

prions

48
Q

what causes incorrectly folded protein in prions?

A

conformational changes are changing protein

Micro (15 decks)

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