Brainscape's Knowledge GenomeTM

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


See full index

Virology > Chapter 9 > Flashcards

Chapter 9 Flashcards

1
Q

Infection

A

presence or growth of a pathogen in the body

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

Viral infection

A

presence or growth of a pathogenic virus in the body
Theoretically, require one virion
Practically, require minimum infectious dose

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

Acute infection

A

Rapid onset, lasts for a short time

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

Persistent infection

A

lasts for a long time

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

Cytocidal infection

A

Cell death

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

To establish infection, a virus must

A
  1. Gain access to a permissive cell

2. Overcome host defense

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

Permissive cells

A

Have receptors for virus to bind
Have all requirements for viral replication
Permit viral replication inside

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

Interferon

A

protein produced by cell in response to viral infection

• α-, β-, and γ-

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

α-, β- interferon

A

produced by virus infected cell to protect nearby cells

bind to interferon receptor -> trigger anti-viral activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

γ- interferon

A

produced by T and NK cells to activate T cell-mediated immunity
Stimulate antigen-presenting, phagocytes, NK cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

NK cell

A

present throughout body, but mainly in blood
• recognize surface change of virus-infected cells
• Bind and kill them by releasing perforin or inducing apoptosis
• Release γ-interferon

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Perforin

A

A pore-forming protein
Produced by killer cells of immune system
-> a channel in cell membrane of target cell-> cell death

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

APOBEC3 proteins

A

enzymes induce lethal mutation: dC->dU during reverse transcription -> interfere with replication of retroviruses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Lymphocytes

A

Key cell in specific(adaptive) immunity

B-cells and T-cells

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

B- cells

A

develope in bone marrow -> antibody-mediated immunity

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

T-cells

A

matured in thymus -> cell mediated immunity
Helper T cells (TH, CD4)
Cytotoxic T Cells (TC, CD8)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Antibodies

A
  • Glycoproteins contain antigen binding sites
  • Ig (immunoglobulins) IgG, IgM, IgA, IgE, IgD
  • Produced by plasma cells derived from B cell
  • Bind specific Ag on virion on infected cells
18
Q

Outcomes of antibody binding to virus antigen

A
  • Neutralization: block virus -> lose infectivity
  • Increase phagocytosis: Fc region binds Fc receptor on phagocyte -> destroy virus
  • Active complement -> cell lysis
19
Q

Helper T cells

A

(TH, CD4)

Stimulate other immune cells by secreting cytokines

20
Q

Cytotoxic T cells

A

(TC, CD8): “killer T cell”

Kill infected cells by releasing perforin or by inducing apoptosis

21
Q

How T cell recognizes cell

A

Te cell receptor recognizes Antigen presented Major Histocompatability Complex class I of infect cell

22
Q

RNA silencing

A

Post transcriptional gene silencing or RNA interference
• Induced by dsRNA
• Destroy sequence specific mRNA (a part of its sequence is the same as a part of inducing ds RNA)
• Dicer: cellular enzyme cleaves dsRNA
• siRNA: small interfering dsRNA (21-25 bp)
• RNA-induced silencing complex
• Activated RISC
o (+) RNA fragment is removed
o (-) RNA bind to mRNA w/ complement sequence
• mRNA cleaved in that region by RISC protein

23
Q

Apoptosis

A

Programmed cell death in animal cell
A series of genetically programmed events leading to cell death
Bacteria have similar mechanism to protect bacterial population

24
Q

Outcomes of virus-infected cell

A

Productive infection

Non-productive infection( no progeny virions produced)

25
Q

Productive infection

A

Produce progeny virus
Cell death or
persistent infection: long term

26
Q

Latent infection

A 
persistent but not productive
Viral genome maintained in infected cell
Integrate into cell genome
Or persist as multiple copies of circular genomes
may be activated by induction
27
Q

Abortive infection

A

Incomplete virus replication

Genome not persisted in infected cell

28
Q

Causes of abortive infection

A

Non-permissive cell
Defective virus
Host defense
Abortive infection may also kill host cell

29
Q

Disease

A

abnormal state of the body resulted from infection, chemical, physical or genetic effects

30
Q

Symptom

A

subjective change in the body, felt by a patient as a result of disease

31
Q

Sign

A

objective changes, observable detectable

32
Q

Incubation Period

A

time between viral entry and appearance of syptoms

33
Q

Viremia

A

virus present in bloodstream

34
Q

Subclinical Infection

A

asymptomatic

35
Q

Carrier

A

infected but asymptomatic

36
Q

Disease in animal/humans

A

Infection may not cause disease
Not all viruses are pathogens
Some viruses are pathogenic only under certain conditions

37
Q

8 Stages in Viral Pathogenesis (animal/human)

A
  1. Entry into host cell
  2. Primary virus multiplication
  3. Spread through host
  4. Host immune responses
  5. Secondary viral multiplication
  6. Cell/tissue injury
  7. Transmission
  8. Resolution, persistence, or death
38
Q

Cell or tissue tropism

A

the tendency of a virus to favor replication in a specific type of cells or tissues

39
Q

Fates of virus-infected host

A

Fate is determined by virus factors, host factors, and environment
Recovery
Persistent Infection
Death(cytocidal infection)

40
Q

Recovery

A

clearance of virus; or become carrier

41
Q

Persistent Infection

A

Chronic: virus always detectable
Latent: dormant, but viral genome is in host cell
Slow: very long incubation period

Virology (17 decks)

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