Middleton- virus structure, classes Flashcards

1
Q

_____ are smaller than bacteria, fungus, and other microorganisms

A

viruses

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

Viruses need what to replicate?

A

a host

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

T/F: viruses are autopoeitic

A

false

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

what is the Cellular origin theory of viruses?

A

Proposes that viruses were once cellular components but over time they evolved separately

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

what is the Autopoietic origin theory of viruses?

A

Proposes that viruses, once autopoietic entities, became dependent on cells for replication.

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

which characteristics are used to classify viruses?

A
Virus particle structure
Genome
Replication features
Serology
Stability
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is a nucleocapsid?

A

RNA or DNA in a core that is protected by a protein coat (capsid)

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

Nucleocapsid is comprised of repeating protein subunits called _______

A

capsomeres

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

what are envelopes?

A

virus-modified cellular membranes acquired upon exit from host

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

what can render an enveloped virus noninfectious?

A

exposure to lipid solvents in the laboratory

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

the ______ of enveloped viruses may differ between viruses

A

nucleocapsids

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

what are the different types of single-stranded RNA?

A

Plus sense ssRNA
minus sense ssRNA
Ambisense

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

name the different structures of viral genomes

A

Linear
Circular
Segmented
Diploid

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

ssDNA hairpin is an example of what?

A

replication of viral genome

“rolling hairpin replication”

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

_____ rolling circle replication takes place on circular genomes of viruses

A

dsDNA

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

The positive strand RNA viruses’ function in same sense as ____

A

mRNA.

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

Before negative strand RNA can be translated, they must serve as template for what?

A

an RNA polymerase

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

the mirror image of a negative strand RNA will be the same as what?

A

positive strand RNA

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

what is the definition of viral attachment?

A

Binding of a virus receptor to a cellular receptor

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

T/F: viral receptors usually do not mimic cell receptors normal ligands

A

true

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

the binding of a virus to a cell receptor can cause what?

A

signaling molecule release
cell adhesion
transport inside the cell

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

_________ is a major determinant of virus tropism (host range)

A

Attachment

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

____ ____ is a major factor in the eradication of a virus

A

Host range

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

how does a virus typically enter the host cell?

A

receptor mediated endocytosis

25
Q

how can non-enveloped virus’s can enter the host cell?

A

through:

1) pores
2) membrane disruptions

26
Q

which protein is responsible for the attachment & fusion of the influenza virus onto the host cell?

A

HA protein

27
Q

after uncoating in the host cell, what can happen to the viral genome?

A

Nuclear or cytoplasmic replication

28
Q

describe what happens during nuclear replication

A
  • Genome and remaining protein coat (nucleocapsid) transported to the nuclear membrane
  • delivery of genome to nucleus
29
Q

describe cytoplasmic replication

A
  • genome released into cytoplasm

- transported to intracellular site of replication

30
Q

___ templates are needed for protein synthesis

A

RNA (mRNA)

31
Q

DNA viruses rely upon cellular __ _____ to produce RNA templates

A

RNA polymerases

32
Q

the genome of (+)ssRNA viruses can serve as what?

A

mRNA

33
Q

(-)ssRNA and dsRNA viruses must bring their own _____ into the cell

A

polymerase

34
Q

viruses need the cell’s ribosomes to produce what?

A

proteins

35
Q

T/F: most viruses need a cells ribosomes to produce proteins

A

False- ALL viruses need them. no exceptions

36
Q

Viral protein production can be regulated at what levels?

A

transcription (mRNA) level

translation level

37
Q

_____ proteins are produced in high quantities during viral translation

A

structural

38
Q

with (+)ssRNA viruses, the ______ serves as a template for translation

A

the genome

39
Q

_______ is needed in (-)ssRNA viruses to copy the template for a new genome

A

Polymerase

40
Q

when (-)ssRNA and dsRNA replicate, the Virus particle must include what?

A

the viral polymerase

41
Q

what is the role of Polymerase?

A

makes messenger RNA for translation

42
Q

dsRNA induces what so that the genome stays inside the particle?

A

innate immune response

43
Q

the mRNA serves what function during dsRNA replication?

A

serves as (+) strand in virus genome

the (-) strand synthesized during assembly

44
Q

both ssDNA and dsDNA must gain access to the ____ for replication

A

the nucleus

45
Q

what proteins aid in assembly of the virus?

A

localize structural proteins

46
Q

during assembly, the genome contains what?

A

packaging signals

47
Q

how are adenoviruses assembled?

A

the empty protein coat imports the genome

48
Q

how are Reoviruses assembled?

A

RNA packaged during capsized assembly

49
Q

how is a retrovirus assembled?

A

pre-assembly on a membrane

50
Q

what are the 2 ways viruses are released from a host cell?

A

Lysis

Budding

51
Q

name the 3 phases of virus replication

A

1) eclipse
2) exponential growth
3) plateau

52
Q

what is meant by the “time for one step growth”?

A

the length of time between start of infection and beginning of plateau phase

53
Q

Fluorescent focus assays use a stain with a labeled ______

A

antibody

54
Q

plaque assay’s use a cell monolayer, which when infected leads to what?

A

the death of cells and the formation of cleared areas (plaques)

55
Q

infectious dose assays use what type of systems?

A

tissue cultures, eggs, animals

56
Q

what are the 2 particle assays?

A

A) electron microscopy

B) hemagglutinin assay

57
Q

viruses bind to red blood cells in which assay?

A

hemagglutinin assay

58
Q

name the 2 genome assays

A

A) PCR- polymerase chain reaction

B) southern (DNA) & northern (RNA) blots

59
Q

name the serological assays

A

1) virus neutralization
2) enzyme link immunosorbant (ELISA)

3) western (protein) blot