Brainscape's Knowledge GenomeTM

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


See full index

AID full > Viruses > Flashcards

Viruses Flashcards

1
Q

What are bacteriophages, and how their structures is different from other human and animal viruses?

A
  • bacteriophage = viruses that lyse bacteria
    Animal viruses capsid enters the cell, bacteriophage do not penetrate
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

how do viruses recognise and bind to their specific host cells?

A

Cellular receptor

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

What is not encoded in viral genomes? why are they not present?

A

complete protein synthesis
proteins involved in cell wall production or membrane biosynthesis
No centromeres or telomers found in standard host chromosomes

  • not there because host cell has them
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

capsomeres?

A

Subunit of the capsid
Smallest morphological unit visible with an electron microscope

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

what is arranged in in icosahedral symmetry? what is arranged in helical?

A

protein subunits of round viruses
why?? = regular stable structure from the smallest number of proteins (60 identical subunits)

protein subunits of rod shaped viruses

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

what is meant by a virus’s particles being metastable

A

stable because they protect - capsid
unstable because they dissociate to give genetic information into cell

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

three types of capsid structures or viruses

A

Helical, Icosahedral, Complex

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

Structural Subunit of capsid definition

A

unit from which the capsid is built- one or more subunit

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

Why do you think capsid is made of one or few proteins that repeat over and over?

A

allow metastability
easy to break but still stable

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

Give examples of the different types of proteins that are encoded for by the viral genome?

A

Structural proteins
Capsid proteins, VAPs

Viral replication: DNA polymerase, RNA polymerase
Pathogenesis
Transformation (HPV and Cervical cancer)
Modulation of host defences

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

what are the Main Criteria for classification of viruses?

A

Nucleic acid
Capsid symmetry
Presence or absence of lipid envelope

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

why can -RNA not be used as mRNA but +RNA can?

A

+RNA has N Sequence identical to the sequence of mRNA whereas –RNA has a sequence that is complementary to the mRNA and cannot act directly as mRNA, it must first be converted to or replicated to +RNA using RNA poly , and only then it can act as mRNA.

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

what makes viroids and prions unconventional viruses?

A
  • viroids contain no proteins just 70% of the nucleotides in the genome RNAs are base-paired - 220 to 400nt
  • prions = no nucleic acid - jus a protein
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the basis of Baltimore system in classifying viruses?

A

the way the virus makes mRNA

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

Identify & describe the major steps in viral replication and use examples

A
  • Recognition
  • Attachment
    -Entry/penetration
    Enveloped: Fusion proteins (HIV) or endosomes /ph change (Influenza)
    naked: Endocytosis or Direct (Poliovirus)
    -Uncoating
    -Protein & NA synthesis
    -Assembly
    -Release - bud or lyse
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

define Viral Tropism

A

The specificity of a virus to a specific host

17
Q

how do dsDNA viruses replicate their DNA?

A

The viral genome is copied or replicated by the DNA polymerases to produce many dsDNA copies
dsDNA - packaged with the viral proteins = many new viral particles/virions

18
Q

What are the different strategies that viruses used to enter the host cell?

A

there are two ways:

19
Q

In viral infections, what determines the host and cell range? Give examples

A

–

20
Q

What are the steps of viral replication?

A
21
Q

What aspect of the life cycle of a virus leads to the sudden increase in the growth curve?

A

the bursting of the host cell that releases all the viral particles

22
Q

What are the main methods of quantifying viruses and how they differ from each other?

A

titre is the main method – many times the main one is a plaque assay but if the virus does not produce these holes in solution, then another method (pathogenicity assays) such as TCID50, AID50 ,LID50assays
are used.

23
Q

What is meant by CPE, give some examples

A

CPE = Cyto Pathic Effects –> Distinct observable cell abnormalities/changes in the cells due to viral infection

24
Q

How would you detect non-CPE producing viruses?

A

Plaque asset relies on CPE –> another method such as EM or Combination of cell culture with PCR has permitted detection of infectious viruses that grow slowly, or fail to produce CPE.

25
Q

What are the main advantages of cell culture for virus growth

A

determine the causative agent of a disease
study its structure, replication, genetics, its effects on host cells,
Vaccine production

26
Q

How can you use hemadsorption to identify viruses?

A

it determines if a virus is able to bind to RBCs on red blood cells

27
Q

What characteristics must a gastrointestinal virus possess in order to effectively infect through this route,

A

not have a capsule as it is dissolved by the harsh conditions of the stomach or bile in the small intestine

28
Q

What is the difference between a susceptible cell and a permissive cell?

A

Susceptible cell:
Expresses the specific receptors that are recognised by a specific virus through specific VAPs

Permissive cell:
Contains the proteins and molecules within the cell that are necessary for replication to occur.

29
Q

What are the different portals of exit of viruses

A

Skin - HPV
GI tract - Poliovirus, rotavirus
Genital tract - HIV, HSV
Conjunctiva - Adenovirus
Viremia - blood
Uraemia - urine

30
Q

What is the difference between pathogenesis and virulence

A

pathogenesis: The ability/capacity of the virus to cause disease
Quantitative or relative measure of the pathogenesis of the infecting virus: Virus A is more virulent than virus B

31
Q

Give specific examples of each of the mechanisms used by viruses to cause injury to cells or tissues

A

4 broad groups:
- Direct cytotoxicity of the virus
- Virus-induced immunopathogenesis
- Virus-induced immune suppression
- Virus-induced transformation

32
Q

What is the different between HIV and AIDS?

A

HIV = virus that infects human
AIDS = the last stage of the three staged of HIV infection where the patient experiences immune system failure
-“characterised by increased susceptibility to opportunity infections”

33
Q

How does AIDS develop?

A

three stages
1. acute stage where the HIV infects CD4+ T cells (possible decrease but not enough to see)
- chromic phase - virus spread & infect helper T cells - Macrophages - dendritic cells –> virus = contained in lymphoid tissue
- AIDS stage - cell destruction + decline in CD4+ T cells in blood
immune - opportunistic infections

34
Q

What is the difference between inactivated vaccines and subunit vaccines?

A

inactivated: contain whole virus which has been killed or have been altered, so that they cannot replicate
subunit: one or more specific component/ unit/antigens usually from the surface of the virus

35
Q

Give examples of viral infections that can be treated by antiviral drugs

A

HIV - Maraviroc /Selzentry or HAART
influenza - AMANTADINE & RIMANTADINE
herpes simplex II - acyclovir

HIV,HCV, Herpesviruses- persistent infections

36
Q

What are the different routes of transmission of viruses?

A

Vertical transmission
respiratory tract
GI (gastrointestinal) tract
genital tract

37
Q

How can virus transmission be interrupted?

A

By 3 methods:
interruption
Vaccination

AID full (4 decks)

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