Brainscape's Knowledge GenomeTM

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


See full index

Baker Semester One > Acellular Pathogens > Flashcards

Acellular Pathogens Flashcards

1
Q

Who postulated that rabies was caused by a virus?

A

Louis Pasteur

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

What did Ivanovski and Beijerinck find?

A

That a disease in tobacco was caused by a virus

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

Viruses

A

noncellular particles with a definite size, shape, and chemical composition

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

Characteristics of Viruses

A

-Infectious, acellular pathogens
-Obligate intracellular parasites with host and cell-type specificity
-DNA or RNA genome (never both)
-Genome surrounded by a protein capsid

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

Host range

A

The range of host species and cell types a virus can infect

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

Phages/bacteriophages

A

Viruses that infect bacteria

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

Vector

A

An animal that transmits a pathogen from one host to another

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

Viruses can be transmitted through…

A

direct contact, indirect contact with fomites, or through a vector

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

Mechanical vectors

A

When the arthropod carries a viral pathogen on the outside of its body and transmits it to a new host by physical contact

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

Biological vectors

A

When the arthropod carries the viral pathogen inside its body and transmits it to a new host through biting

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

Capsids

A

-Protein coat that encloses and protects the nucleic acid of the virus
-Made up of capsomers
-All viruses have them

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

Capsomers

A

Identical protein subunits which make up facets of the capsid

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

Viral Envelope

A

-An external covering around the virus (including around the capsid)
-Most animal viruses
-Acquired when the virus leaves the host cell
-Spikes (exposed proteins on the outside of the envelope) help with attach of the virus to the host cell

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

Naked virus

A

Lacks an envelope

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

Helical virus

A

Continuous helix of capsomers forming a cylindrical nucleocapsid

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

Polyhedral or Icosahedral capsid

A

A three dimensional, 20-sided structure with 12 ventricles

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

What are the functions of the Capsid/Envelope?

A

-Protects the nucleic acid when the virus is outside the host cell
-Helps the virus bind to a cell surface and assists the penetration of the viral DNA or RNA into a suitable host cell

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Why are poxviruses complex/atypical?

A

They lack a typical capsid and are covered by a dense layer of lipoproteins

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Viral genome

A

-Either DNA or RNA but never both
-The number of genes varies for each type of virus
-Carries genes necessary to invade host cell and redirect cell’s activity to make new viruses

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are the main criteria presently used to classify viruses?

A

-Viral genetics
-Chemistry
-Morphology
-Mechanism of multiplication

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Family name of a virus ends in

A

-viridae

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Genus name of a virus ends in

A

-virus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

DNA viruses

A

-Usually double-stranded but may be single-stranded
-Circular or linear

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

RNA viruses

A

-Usually single-stranded
-May be double-stranded
-May be segmented into separate RNA pieces
-Positive sense or negative sense

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Positive-sense RNA

A

ssRNA genomes ready for immediate translation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Negative-sense RNA

A

ssRNA genomes that must be converted into proper form (positive sense RNA)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Cornavirus (Family of Coronaviridea)

A

-Enveloped and have non-segmented, ssRNA+ (single-stranded, positive sense RNA)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

General Lytic Cycle of a Virulent phage

A
  1. attachment
  2. penetration
  3. biosynthesis
  4. maturation
  5. lysis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Attachment portion of lytic cycle

A

The phage attaches to the surface of the host

30
Q

Penetration portion of lytic cycle

A

The viral DNA enters the host cell

31
Q

Biosynthesis portion of lytic cycle

A

phage DNA replicates and phage proteins are made

32
Q

Maturation portion of lytic cycle

A

New phage particles are assembled

33
Q

Lysis portion of lytic cycle

A

The cell lyses, releasing newly made phages

34
Q

Temperate/Lysogenic Phage

A

The phage integrates its genome into the host bacterium’s chromosome as a prophage– Does not lyse the cell immediately

35
Q

Prophage

A

A bacteriophage genome that’s integrated into a bacterial cell’s chromosome or exists as plasmid

36
Q

Lysogeny

A

A viral reproduction cycle where a phage’s DNA integrates into a host bacterium’s genome and the viral DNA is retained and copied during the bacterial cells normal cell division, resulting in a transfer of the temperate phage genome to all host cell progeny

37
Q

Lysogenic cycle of a virulent phage

A
  1. Attachment
  2. Penetration
  3. Phage DNA becomes incorporated into host genome
  4. Cell divides and prophage DNA is passed onto daughter cells
  5. Under stressful conditions the prophage DNA is excised from the bacterial chromosome and enters the lytic cycle
  6. Biosynthesis
  7. Maturation
  8. Lysis
38
Q

Induction

A

the process by which a temperate phage switches from the lysogenic state to the lytic pathway

39
Q

Hepatits B Host range

A

Human liver cells

40
Q

Poliovirus host range

A

primate intestinal and nerve cells

41
Q

Rabies host range

A

various cells of many mammals

42
Q

Endocytosis of a virus

A

Entire virus is engulfed and enclosed in a vacuole or vesicle

43
Q

Fusion of a virus to a cell membrane

A

Envelope merges directly with membrane resulting in nucleocapsids entry into cytoplasm

44
Q

Viral uncoating

A

the breakdown or removal of the capsid causing the release of the viral genome into the cell

45
Q

Where are DNA viruses generally replicated?

A

In the nucleus

46
Q

Where are RNA viruses generally replicated and assembled?

A

in the cytoplasm

47
Q

Budding (exocytosis)

A

Nucleocapsid binds to membrane which pinches off and sheds the viruses gradually; cell not immediately destroyed

48
Q

Lysis

A

Nonenveloped and complex viruses released when cell dies and ruptures

49
Q

Cytopathic effects (virus-induced damage to cells)

A

-Changes in size and shape
-Cytoplasmic inclusion bodies
-Inclusion bodies
-Cells fuse to form multinucleated cells
-Cell lysis
-Alter DNA
-transform cells into cancerous cells

50
Q

Persistent infections

A

cell harbors the virus and is not immediately lysed

51
Q

Chronic latent virus

A

a virus that remains in the body for a long time without causing symptoms but can reactivate later to cause repeat infection

52
Q

Examples of persistent infections with a chronic latent state

A

-Measles virus
-Herpes simplex virus
-Herpes zoster virus

53
Q

Herpes simplex virus

A

cold sores and genital herpes

54
Q

Herpes zoster virus

A

chickenpox and shingles

55
Q

Oncoviruses

A

mammalian viruses capable of initiating tumors

56
Q

Papillomavirus

A

An oncovirus responsible for cervical cancer

57
Q

Epstein-Barr virus

A

An oncovirus responsible for Burkitt’s lymphoma

58
Q

Steps in Transduction

A
  1. Viral attachment and penetration
  2. Integration
  3. Excision
  4. Infection
  5. Recombination
59
Q

Integration step in transduction

A

the phage DNA becomes incorporated into the host genome

60
Q

Excision step in transduction

A

The phage is excised from the bacterial chromosome along with a short piece of bacterial DNA. The DNA is then packaged into newly formed capsids

61
Q

Infection step in transduction

A

Phage containing both viral and bacterial DNA infect a new host cell

62
Q

Recombination step in transduction

A

The phage DNA, along with the attached bacterial DNA, are incorporated into the new cell

63
Q

Differences in Bacteriophage and Animal Virus Multiplication

A

-In bacteriophage, there is the precise attachment of special tail fibers to cell wall whereas in animal virus there is attachment of the capsid or cell envelope to cell surface receptors
-In bacteriophage there is no uncoating of the nucelic acid, it is injected through the cell wall. In animal viruses the whole virus is engulfed and uncoated or viruse fuses with cell memrbane

64
Q

Techniques in Cultivating and Identifying Animal Viruses

A

-Cell cultures
-Bird embryos
-Live animal inoculation

65
Q

Prions

A

-misfolded proteins, contain no nucleic acid
-Extremely resistant to usual sterilization techniques
-Cause transmissible spongiform encephalopathies (fatal neurodegenerative diseases)

66
Q

Prion diseases common in animals

A

-Scrapie (goats and sheep)
-Bovine spongiform encephalopathies (mad cow disease)
-Wasting disease (elk)
-Creutzfeldt-Jakob Syndrome
(humans)

67
Q

Satellite viruses

A

Dependent on other viruses for replication

68
Q

Adeno-associated virus

A

A satellite virus that replicates only in cells infected with adenovirus

69
Q

Delta agent

A

A satellite virus with a naked strand of RNA expressed only in the presence of hepatits B virus

70
Q

Viroids

A

short pieces of RNA, no protein coat; only identified in plants

71
Q

Latent infection vs Chronic infection

A

Latent remains hidden and dormant in cell during a phase called latency
Chronic is consistent or recurrent over a long time

Baker Semester One (6 decks)

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