Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

IVP > Microbiology 2 > Flashcards

Microbiology 2 Flashcards

1
Q

What is the structure of a virion?

A
  • Genome composed of RNA or DNA (not both)
  • Surrounded by a delivery system - a protein shell (capsid/nucleocapsid)
  • In some cases a lipid envelope
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the function of a capsid (in virus)?

A
  • Protects the genome
  • Deliver genome into cell
    > capsid proteins bind to cell receptors, trigger uncoating and ensure genome ends up in correct place within cell
  • Made of large number of identical protein subunits
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Viruses can be classified according to:

A
  • Nature of the nucleic acid (DNA or RNA) and genome type (ds/ss/sense)
  • Presence of envelope

> there are a number of different criteria but these are most important.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is an example of a non-enveloped DNA virus?

A

Canine parvovirus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is an example of an enveloped DNA virus?

A

Feline herpesvirus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What is an example of a non-enveloped RNA virus?

A

FMD virus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What is an example of an enveloped RNA virus?

A

Influenza virus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are some features of DNA viruses?

A
  • DNA stable
  • Most replicate in nucleus
  • Viral DNA replication
  • DNA viruses less prone to mutation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are some features of RNA viruses?

A
  • RNA is labile and transient (unstable)
  • Most replicate in cytoplasm
  • Cells cannot copy RNA from RNA.
    RNA viruses must provide own RNA dependent RNA polymerase
  • RNA viruses prone to mutation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are features of enveloped viruses?

A
  • fragile in envt
  • do not survive adverse conditions
  • easily inactivated by disinfectants
  • Exit cells by lysis or budding and syncytia
  • Require both CELL-MEDIATED and HUMORAL immunity
    e. g. Herpes virus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are features of non-enveloped viruses?

A
  • very stable
  • more resistant to acid, heat, cold, proteases, detergents, drying
  • Exit host cells only by lysis
  • Antibody (acquired o passive) directed at virus usually protective
    e. g. canine parvovirus (DNA), FMD virus (RNA)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is meant by ‘viral tropism’?

A

Capacity to enter and interact with host to cause disease.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Discuss how mutation in the viral genome can alter the host range and virulence?

A
  • Mutation is a structural alteration in the nucleic acid (genotype)
  • Can have a -/neutral/+ effect on the fitness of the virus
  • Mutation can have important effects on:
    > Virulence of virus
    > Host range of virus
  • Point mutation, Insertions, deletions
  • Viral recombination = transfer of genetic material between different but closely related viruses infecting the same cell.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is antigenic drift?

A

Gradual accumulation of point mutations (more common)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is antigenic shift?

A

Acquisition of a new gene from another virus - particularly common in some viruses e.g. Influenza - due to recombination of reassortment (relatively rare).

Viruses can “co-infect” to exchange genomic material.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Describe the types of virus-cell interactions that occur using examples of viral diseases that have this type of interaction.

A
  1. Lytic infections (cytocidal) e.g. Parvovirus, FMD
  2. Persistent infection
    - -> Productive e.g. rabies, FMD
    - -> Latent e.g. herpes, retrovirus
    - -> Non-productive transforming e.g. retroviruses, equine sarcoid
17
Q

What are the effects of viral infection on cell morphology?

A
  • Cytopathic effect: effects seen in cell monoculture
  • Inclusion bodies: Morphological changes, Intranuclear (DNAv) or intracytoplasmic (RNAv). not all viral infections produce inclusion bodies (e.g. Calici v)
  • Alterations in cell membranes: Increase permeability, ion exchange/membrane potential, proliferation and rearrangement of membranes, Insertion of viral glycoproteins
  • Formation of syncytia: Viral proteins inserted into plasma membrane of one cell may lead to fusion between neighbouring cells
  • Haemadsorption: Cell in culture infected with some viruses may acquire the ability to absorb RBC due to presence of viral glycoproteins on membrane
18
Q

How do viruses damage cells?

A
  • Cell lysis
  • Inhibit host cell nucleic acid synthesis/ shutdown protein syntehsis
  • Cytopathic Effects of toxic viral products
  • Cyolysis by immunologic mechanisms
19
Q

Outline the routes of viral entry and discuss host defence at the sites.

A
  • Respiratory system: most common e.g. Influenza, FMDV and some herpesviruses.
    Distance particles travel into the RT depends on their size
    Nasal passages, Nasopharynx, Larynx, LRT
  • Alimentary system: hostile envt. for viruses (most common are non-enveloped). Peristalsis, Mucous, Bile, Proteases, Gastric Acid, Peyer’s patch
  • Skin: keratinised layer. Dead cells continual shedding.
  • Conjunctiva: FHV. Tear producing
  • Urogenital tract: urinary flushing, anatomical barriers, low pH, secretory IgA

IVP (3 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions