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Virology > Week 1 Lectures > Flashcards

Week 1 Lectures Flashcards

1
Q

Define the term virus.

A

Virus means slimy liquid or poison.

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2
Q

Viruses are submicroscopic __________ (______ microns) infectious agents that multiply only in _________ _______.

A

filterable, < 0.2, living cells.

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3
Q

List three examples of mediums in which viruses can grow.

A

Agar agar
M. Agar
Chicken eggs

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4
Q

Viruses are __________ parasites that are metabolically inert when they are ________ their hosts.

A

obligate, outside

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5
Q

Define obligate parasites.

A

Obligate parasites must be inside a cell to replicate.

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6
Q

Viruses rely, to varying extents, on the __________ _________ of their hosts to _______ ________.

A

metabolic processes, reproduce themselves.

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7
Q

True or False: Do viruses have cellular organelles?
Give examples.

A

No
Mitochondria, chloroplasts, GA, ER, ribosomes.

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8
Q

Viruses have nucleic acids in the form of ______ or _______ but _______ both except in the case of ___________.

A

DNA, RNA, never, retroviruses.

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9
Q

Virions are the _________ ________ __________ viral particle produced by the ________ cells under the control of the _______ materials of the virus.

A

mature, extracellular, infectious, infected, genetic

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10
Q

Viroids are infectious entities that affect _______, are ________ than a virus and consist only of nucleic acids without a ________ _______.

A

plants, smaller, protein coat

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11
Q

Satellite or Defective Viruses require a _______ _______ (_______ virus) for replication.

Provide an example.

A

second, virus, helper
Ex: Hepatitis delta virus requires the presence of HBV to complete its replication cycle.

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12
Q

Living Criteria of viruses
Inside the virus permissive cells
• Viruses ____ and ____ cellular functions for their own purposes
• Viruses can ____
- ___ genome
- _____ code
- new viral components are ______ and _______ within the infected ____ cell
• Viruses may undergo _____ which affect the genotype which will be reflected phenotypically in the virus structure.

A

control, divert, multiply, viral, genetic, synthesized, assembled, host, mutations

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13
Q

Nonliving criteria of viruses
• Viruses are not able to ______ on their own
• Viruses must infect ___ cells in order to perpetuate their life cycle
• Viruses can be _______ but no other cells can be
• Viruses do not have _____ generating (___) machinery
• Viruses do not have _____ machinery
• Viruses do not have the necessary machinery for generating ______ ___ or ____
• Viruses do not contain ______ or any _____ _____
• Viruses may contain ______ ______ derived from the infected host cells during viral exit

A

reproduce, other, crystallized, energy, ATP, metabolic, nucleic acid, protein, cytoplasm, cellular organelles, membranous envelope

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14
Q

Describe the non-life viral theory
Viruses are considered to be non-living because they
-Are not ___
-Do not ____ or respond to their ______
-Can not make ___, take in ____, or produce _____
-They do not respond to ____

A

cells, grow, surroundings, food, food, wastes, stimuli

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15
Q

Describe the life viral theory
The viral life theory has only two fundamental characteristics of the living system
1- the presence of ____ ____ as genetic material
2- the ability to _____ and produce their own ___.

Viruses can only multiply in _______
_____

A

nucleic acid, replicate, copies,another cell

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16
Q

Are viruses living or non-living?

A

Conclusion: viruses are nonliving outside the cells but live inside the cell

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17
Q

Which of the following can be isolated and propagated on synthetic media?
A. Bacteria
B. Mycoplasma
C. Rickettsia
D. Chlamdyia
E. Viruses

A

Yes: Bacteria, mycoplasma
No: Rickettsia, Chlamydia, Viruses

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18
Q

Which of the following can undergo binary fission?
A. Bacteria
B. Mycoplasma
C. Rickettsia
D. Chlamdyia
E. Viruses

A

Yes: A, B, C, D
No: E
Viruses replicate in a different way

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19
Q

Which of the following contain both RNA and DNA?
A. Bacteria
B. Mycoplasma
C. Rickettsia
D. Chlamdyia
E. Viruses

A

Yes: A, B, C,D
No: E

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20
Q

Which of the following contain energy machinery?
A. Bacteria
B. Mycoplasma
C. Rickettsia
D. Chlamdyia
E. Viruses

A

Yes: A-D
No: E

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21
Q

Which of the following are effected by antibiotics?
A. Bacteria
B. Mycoplasma
C. Rickettsia
D. Chlamdyia
E. Viruses

A

Yes: A-D
No: E

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22
Q

Which of the following can perform metabolism?
A. Bacteria
B. Mycoplasma
C. Rickettsia
D. Chlamdyia
E. Viruses

A

Yes: A-D
No: E

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23
Q

Which of the following is greater than 300 nm in size?
A. Bacteria
B. Mycoplasma
C. Rickettsia
D. Chlamdyia
E. Viruses

A

Yes: A-D
No: E

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24
Q

Which of the following can be detected by light microscopy?
A. Bacteria
B. Mycoplasma
C. Rickettsia
D. Chlamdyia
E. Viruses

A

Yes: A-D
No: E
Most viruses can only be seen under EM except in cases of giant viruses as Mimivirus can be seen by light microscope.

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25
Q

Which of the following have a sensitivity to interferons?
A. Bacteria
B. Mycoplasma
C. Rickettsia
D. Chlamdyia
E. Viruses

A

Yes: E
No: A-D

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26
Q

Which of the following possess a cell wall?
A. Bacteria
B. Mycoplasma
C. Rickettsia
D. Chlamdyia
E. Viruses

A

Yes: A, C, D
No: B, E

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27
Q

Mutation rates are primarily determined by the type of _____ _____ ______.
_________ mutation may not cause changes genotypically or phenotyically. Viruses mutate frequently, rate of mutation of DNA viruses is ____ then RNA viruses. Most viruses that spread rapidly are ____ viruses.

A

viral nucleic acids
Ongoing, less, RNA

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28
Q

A viruses “order” is defined as a group of virus ______ sharing certain ______ _________.

A

families, common characteristics

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29
Q

A viruses “family” is defined as a group of _____ sharing certain common characteristics with ____ _____.

A

genera, each other

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30
Q

A virus’ “sub-family” is defined as a group of genera sharing common characteristics and is used only when it is needed to solve a complex _______ problem.

A

hierarchical

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31
Q

A virus “genus” is defined as a group of ______ species that share some significant ______. Usually only differ in host _____ and _____.

A

related, properties, range, virulence

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32
Q

A virus “species” consists of a few words and must not consist only of a ?

A

host name.

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33
Q

Describe the physical properties of viruses
- Type of viral ____ ____
- The nucleic acid could be ______ ______ (ss) or ______ ______ (ds)
- viral ____
- ______ of viruses
- total number of _______ per virus
- presence or absence of the viral ______.

A

nucleic acid, single stranded, double stranded, size, symmetry, capsomeres, envelope

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34
Q

What are the two major chemical properties of viruses?

A

Heat sensitivity
pH sensitivity

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35
Q

Describe the biological properties of viruses
- Cytopathology (CP): specifically?
- Hemagluttination property
- Antigenic properties

A

site of replication (IC or IN), inclusion bodies

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36
Q

Inner core: is made up of _____ _____.
- Always occupy the _____ region of the virus
-Usually _______ to packed into a small space
-May be ______ _____ (ds) or _____ ______ (ss)
-ds: most of the ____ viruses; exception?
-ss: most ___ viruses; exception; exception?
-Sometimes segmented: examples?

A

Nucleic acids, central, coiled, double-stranded, single-stranded, DNA, Parvovirdae and Circovirdae (ss), RNA, Reoviridae and Birnavirdae (ds), Influenza viruses, Reovirues, and Birnaviruses

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37
Q

Outer membrane is made up of Viral ______
-Surrounds the ______ _____
-composed of ______ subunits called ______

A

capsids, nucleic acids, repeated, capsomeres

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38
Q

• Additional outer layer consists of Viral _____, ____
- _____-_____ layer acquired from the cell membrane of the _______ cells
- Usually covered with some projections called ________
- Non enveloped viruses are called ______ viruses
- Examples of enveloped viruses: ?

A

envelopes, peplos, Lipo-protein, infected, peplomers, naked, Coronaviridae, Influenza viruses

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39
Q

Viruses can be classified based on?

A

Nucleic Acids = DNA or RNA
Symmetry = Helical, Icosahedral, Complex
Envelope = Enveloped, Naked

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40
Q

The Capsid is the protein ____ surrounding the ____ _____. Capsomeres are the structural _______ of the _____.

Function of viral capsids
- Protects viral _____
- Serves as an ______ protein (only in the case of ______ /___-______ viruses) and bind the virus to susceptible _____ cells thereby promotes virus ____ into cells
- Stimulate the immune response to produce _______ against the virus
- Facilitates the ______ and _______ of the viral genetic materials.

A

shell, nucleic acid, subunits, capsid
genome, attachment, naked, non-enveloped, host, entry, antibodies, assembly, packaging

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41
Q

Helical symmetry viruses have:
-Capsomers arranged around the ____ ____ in a ______ fashion.
-Capsomers attached ______ to the helix of _____ _____.
-Most of the helical viruses are ______, and all are ____ viruses
-Examples: ?

A

nucleic acids, helical, directly, nucleic acids, enveloped, RNA, TMV

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42
Q

2- Icosahedral symmetry viruses or ____ have
-Capsomeres arranged around the _____ _____ in a ______ fashion
-Capsomers form a regular icosahedron composed of ___ ______ triangular facets
- Two types: _______ or ______ at vertices
- Examples: ?

A

cubic, Nucleic acids, icosahedral, 20, equilateral, pentagons, hexagons, Adenovirus, Picornavirus, Papovavirus, herpes

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43
Q
  • 3- Complex symmetry viruses:
  • ______, ______, _______, has a unique complex structure
A

Poxvirus, Bacteriophages, retroviruses

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44
Q

Label the image below

A

Naked icosahedral
The entire structure is a nucleocapsid
label on right = capsid

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45
Q

Label the image below

A

Naked helical
Label on left = capsid
Entire thing = nucleocapsid

46
Q

Label the image below

A

Enveloped helical

47
Q

Label the image below

A

Enveloped icosahedral

48
Q

Label each of these accordingly

A

Capsomeres
Nucleic acid
Spikes/peplomers (glycoprotein)
Envelope (protein + lipid)

49
Q

Identify the virus below

A

Rabies

50
Q

Identify image below

A

Adenovirus

51
Q

Identify the virus below

A

Influenza virus

52
Q

Label the image below

A

Coronavirus
crown shape = spike glycoproteins

53
Q

Identify the virus below

A

Ebola virus

54
Q

The outer shell of the viral envelope surrounds the viral ______. The viral envelope itself is composed of a ____ _____ derived from the ____ cell membrane during the virus ____ from the cell and is composed of _______.

A

nucleocapsid, lipid bilayer, host, exit, glycoproteins

55
Q

What are the functions of the viral envelope?

A
  1. Protects the viral nucleocapsid
  2. Mediates viral attachment and entry into host cells; HA in case of influenza viruses, spike in case of coronaviruses
  3. Mediates viral entry into the host cells
56
Q

Enveloped viruses are sensitive to _____ ______ and common _______.

A

lipid solvents, disinfectants

57
Q

Some viruses have projections called _____ or _______. Viruses may have one or more type of ______ (influenza virus, NDV, etc). Some viral peplomers have ____ function, while others have ____ or _____ functions. Give examples of each.

A

spikes, peplomers, peplomers, one, dual, multiple.
Example of virus with one function: HA peplomers in influenza viruses: Hemaagluttinations some RBCs.
Example of virus with dual function: HN peplomers in paramyxoviruses have two functions.

58
Q

_______ causes elution of the agglutinated RBCs and facilitates the virus entry.

A

Neuraminidase

59
Q

Some viral peplomers induce fusion of various cells together to form _______.

A

syncytium

60
Q

Viral peplomers have some _________ properties.

A

antigenic

61
Q

(+Ve) sense (Polarity)
Viral genome act as a ________ _______ (____)
Viral genome hook onto the _____ cell ______ directly then translated into _______.

A

messenger RNA, mRNA, host, ribosomes, proteins

62
Q

(-Ve) sense (Polarity)
The genome must be transcribed into _______ copy before ______.

A

complementary, translation

63
Q

All DNA viruses have ds genomes except?

A

Parvoviridae, circoviridae

64
Q

All RNA viruses have SS genomes except?

A

Reoviridae, birnaviridae

65
Q

Viral genetic materials function to:
1. Carries the ______ ______ for the progeny production
2. Codes for the synthesis of viral ______ required for viral _______.
3. Codes for the synthesis of viral ______ _____ required for viral assembly

A

genetic blueprint, enzymes, replication, structural proteins

66
Q

(+Ve) Sense is a strand of viral ____ that can immediately serve as a template _____ for _____ synthesis during the process of ______. Examples are?

A

RNA, mRNA, protein, translation
Toga, corona, picorna, flavi

“Tuck christine’s panties, fanks!”

67
Q

(-Ve) sense is defined as a strand of viral ____ that must first be converted into _______ _____ sense strands before creating _____. Examples are?

A

RNA, complementary positive, proteins
Mononegavirales (filo, borna, paramyxo, rhabdo, orthomyxo, arena, bunya).

Mom finds bunnies, parrots, rodents, octopi, and babies.

68
Q

An ambisense is an ____ viral genome that is in part of ____ and in part of ____ polarity. Both nucleic acid strands encode _____. Examples are?

A

RNA, positive, negative, proteins
Arenavirus, phlebovirus, tospovirus, tenuivirus

Are puppies that tiny?

69
Q

Some Physiochemical properties of viruses

A
70
Q

______ pH: is optimum for the growth and multiplication of most viruses

A

Neutral

71
Q

•Extreme ______ and ______: media are deleterious to most viruses

A

acidic, alkaline

72
Q

•pH ___: is detrimental to most viruses
- Exception: ?

A

10
African swine fever virus (ASFV) – stable at pH 4-13

73
Q

What products can be used to denature viral proteins?
1. _______ derivatives (_____)
2. ______ compounds (______)
3. Sodium ______ (____)/______ agent
4. Hydrogen ______/______ agent
5. _____ (mixture of _____ and surfactant) - ______ agent

A

Phenol, lysol, Ammonium, Roccal, hypochlorite, clorox, oxidizing, peroxide, oxidizing, Iodophors, iodine, oxidizing

74
Q

How can viral proteins be inactivated?

A

You first soak the viral solution in 1 N NaOH and then autoclave it for 1.5 hours.

75
Q

How can you denature both viral proteins and viral nucleic acids? Describe the mechanism of action.

A

Formaldehyde (1-5%), Glutaraldehyde (2%), Ethylene oxide (fumigation) - extremely toxic (must be in a sealed chamber), UV light (cross links the pyrimidine bases (C & T/U).

Mechanism of action: Incorporate short chain of carbon atoms to the viral proteins and NA leading to degradation.

76
Q

How can viral envelopes be dissociated?

A

70% alcohol mixed with water results in lipid disruption and denaturing of proteins.

77
Q

Baculoviruses: modified by genetic engineering to express some other viral proteins for _____ _____ as well as development of some novel ______ _____.

A

vaccine purposes, diagnostic assays

78
Q

_____ and ______ used as viral vectors

A

Poxviruses, Adenoviruses

79
Q

Lentiviruses: modified to insert some _____ ____ of interest into cells for _____ purposes and ______ ______.

A

foreign genes, research, gene therapy

80
Q

Bacteriophages: used in the control of some _______ infections.

A

bacterial

81
Q

Viruses specifically infect ______ and are obligate _______ parasites. Viruses infect various bacterial species, but most extensively investigated phages
infect ____ bacteria, ___ ____ and _______.
• Phages can be ____ or ____ and either _____ or _____-stranded.
• They have a _____ (head), a ____, and ____ fibers, which are _____. The
capsid has the ____. The tail fibers attach to the bacterial ____ _____ and inject the ____ into the cell.

A

bacteria, intracellular, enteric, E. coli, Salmonella, DNA, RNA, double, single, capsid, sheath, tail, contractile, DNA, cell surface, DNA

82
Q

Label the image accordingly.

A

Green = head
Blue = collar
Purple = tail
Orange = tail pins
Yellow = end plate
Pink = tail fibers

83
Q

Phages multiply by one of two
alternative mechanisms:
1. The Lytic Cycle: the host bacterial cell is ______ (_____ phages)

  1. The Lysogenic Cycle: host bacterial
    cell remains _____ and _____. The life cycle results in a _____ genetic relationship with the _____. The phages are called ______ phages.
A

lysed, lytic, intact, alive, stable, host, temperate

84
Q

Phage therapy is the therapeutic use of _____ bacteriophages to treat ________ infections

A

lytic, bacterial

85
Q

Most phages are specific to _____ species of bacteria, and many are only able to lyse
specific _______ ______ a species. The limited host range can be advantageous, in principle, as phage therapy results in _____ _____ to the ______ body _____ and ecology than commonly used _______.

A

one, strains, within, less harm, normal, flora, antibiotics

86
Q

Lytic phages are similar to ______ in that they have remarkable ______ activity. However, therapeutic phages have some advantages over antibiotics. Phages have been reported to be _____ effective than antibiotics in treating certain infections in humans and experimentally infected animals. List two examples.

A

antibiotics, antibacterial, more
Ex:1: Staphylococcal aureus phages were used to treat patients having the purulent disease
of the lungs and pleura
Ex: 2: Phages are used to reduce E. coli O157:H7 (a food-borne pathogen) on hide surface
of cattle before slaughter
• Bacteria can also develop resistance to phages

87
Q

Describe the image below

A

Phages docking on a bacterium

88
Q

Explain the image describing Koch’s postulates below

A
89
Q

What does Koch’s postulates emphasize?

A

It is crucial to show that the virus is isolated from many animals that have the same disease.

90
Q

What types of samples do you need to obtain for respiratory viruses?

A

Nasal, oropharyngeal swabs, fecal swabs, blood and serum.

91
Q

What types of samples do you need to obtain for enteric viruses?

A

-Fecal swabs, feces, blood, serum in the live -Cattle (Rotavirus, Coronavirus, animals BVDV
-Parts from the organs of the digestive system such as intestine
Antemortem and postmortem

92
Q

What types of samples do you need to obtain for vesicle-forming viruses?

A

-Vesicular fluids, saliva, blood, serum

93
Q

What types of samples do you need to obtain for skin lesion producing viruses?

A

Scabs from different regions in the body

94
Q

What types of samples do you need to obtain for nervous manifestations viruses?

A
  • CSF, blood, sera, some brain tissues
95
Q

Example of respiratory viruses

A

NDV, IBV, ILT in poultry
IBRV in cattle

96
Q

Example of enteric viruses

A

Cattle (Rotavirus, Coronavirus, BVDV).

97
Q

Example of vesicle forming viruses

A

FMDV, VSV, MCFV

98
Q

Example of skin lesion producing viruses

A

Cow pox, camel pox, lumpy skin disease

99
Q

Example of nervous manifestations

A

Rabies virus in animals
NDV in chicken

100
Q

-Refrigerator temperature (4 °C): enough for the preservation of samples for ?

A

up to 24 hrs.

101
Q

-Deep freezer temperature (-20 to -40°C): samples for ?

A

several weeks to a few month

102
Q

Deep freezer (-80°C): enough to preserve samples for?

A

a few years

103
Q

Liquid nitrogen (-196°C): enough to preserve samples for ?

A

many years

104
Q

Lyophilization: (______ drying) as the viral suspension should be subjected to _____ pressure and ____ temperature, then the lyophilized material may store at ___ °C for a longer time.

A

freeze, high, low, 4

105
Q

How do you process virology samples collected from body secretions and excretions?

A

• Body secretions or execrations in the form of liquids
-saliva, nasal swabs, -oropharyngeal swabs
1- Clarified by centrifugation at 3000 RPM
2- Supernatants should be collected and antimicrobial agents
-antibiotic cocktail (pensile and streptomycin) and -antifungal such as Fungizone should be added
to prevent any bacterial or fungal contamination tot eh virology samples
3- Samples should be stored at the appropriate temperatures until processed further

106
Q

How do you process serum samples?
•The blood should be collected ________ adding any anticoagulants to obtain the _______.
•The tubes containing blood samples should be kept in ______ position at ___C for overnight or incubated at ___ C for ____ ____
•_________ of the tubes at 5000 rpm for ___ min
• ________ of the serum samples and transfer to new clean labeled tubes.

A

without, serum, oblique, -4, 37, 1 hr, Centrifugation, 10, Aspiration

107
Q

Whole blood: collected on anticoagulants such as ______ or ______ _______ then subjected to low speed centrifugation at _____-______ rpm for 10 min
The blood will then separated into?

A

EDITA, sodium citrates, 1500-2000
-Plasma, Buffy coat : blood platelets and leukocytes and RBCs at the bottom

108
Q

Usually viruses can be isolated from ?

A

the Buffy coat

109
Q
A

PBMC = peripheral blood mononuclear cell

110
Q

How do you process tissue specimens for virology diagnostics?

A

Parts from the target organs collected under aseptic conditions. About 1 gram of each organ should be excised by sterile clean scalpel or scissor.
The tissue pieces should be placed in a sterile mortar and
10 % tissue suspension should be prepared using 9 ml of PBS with the help of sterile sand . The obtained tissue suspension should subjected to three cycles of freezing and thawing Then to low speed centrifugation at 3000 rpm for 15 min at (4° C) Collection of the supernatant should be done and stored at (– 80 °C)
till use

111
Q
A

Virology (17 decks)

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