Brainscape's Knowledge GenomeTM

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


See full index

Nancymedsci202 > Lecture 17: Intro To Virology > Flashcards

Lecture 17: Intro To Virology Flashcards

0
Q

What therefore must viruses be to endure nature?

A

Infectious

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

Why are viruses not living organisms?

A

They cannot produce energy or proteins independently of a host cell

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

What must viruses be able to do

A

Use cell processes

Encode any required proteins not provided by the host. E.g. Special enzymes like reverse transcriptase, RNA dependent RNA polymerase etc

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

What sort of agents are viruses? (Due to their small size)

A

Filterable agents. - I.e. they cannot be removed by microfilters

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

What can viral genomes be?

A

Either DNA or RNA but NOT both

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

What morphologies do viruses have?

A

Naked capsid or

Envelope morphology

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

How are viral components different to Bacterial components?

A

They are assembled (self assembly)

They do not replicate by division

Viruses don’t grow in size, they grow in number

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

How can viruses be classified?

A 
structure,
biochemical characteristic
Disease
Means of transmission
Host cell
Tissue or organ
Members of particular family
Location of first isolation
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How are viruses classified by structure?

A

Structure classification by size, morphology, nucleic acid,

E.g. Picornavirus (means small RNA )

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

How can viruses be classified by their biochemical characterstics?

A

By their structure, mode of replication

E.g. Togavirus (means mantle envelope),
retrovirus (which converts RNA to DNA )

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

How can viruses be classified by their disease?

A

Classified by the disease they cause

E.g. Encephalitis virus, hepatitis virus, poxvirus

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

How can viruses be classified by their means of transmission?

A

E.g. Arbovirus means spread by insects

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

How can viruses be classified by the host cell?

A

By the type of host they infect.

Animal, plant, bacteriae, e.g. Bacteriophage

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

How can viruses be classified by tissue or organ?

A

Classification by the tissue or organ they infect,

e.g. Adenovirus and enterovirus.

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

How can viruses be classified by members of a particular family?

A

E.g. Papovavirus (including papilloma, polyoma, vacuolating virus)

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

How can viruses be classified by their location of their first isolation?

A

E.g. Coxsackievirus found in cocksackie, NY

16
Q

List the human DNA viruses in order of increasing size

A 
Parvovirus
Papovavirus
Adenovirus
Herpesvirus
Poxvirus
17
Q

Name the human RNA viruses in order of increasing size

A 
Picornavirus
Reovirus
Togavirus
Coronavirus
Orthomyxavirus
Rhabdovirus
Paramyxovirus
18
Q

List the viruses that infect bacteria in order of increasing size

A

Bacteriophage MS2
Bacteriophage M13
Bacteriophage T2

19
Q

What is a virus that infects plants?

A

Tobacco mosaic virus

20
Q

Name the main components of a virus

A 
Glycoproteins
Bilipid layer
Nucleic acid
Capsid 
Capsomere
(Envelope)
21
Q

What are the features of a naked capsid virus

A

Environmentally stable to temperature, acid, proteases, detergents and drying

Released from cell by lysis

Can be spread easily (e.g. By dust, hand to hand contact)

Can dry out BUT still contain infectivity

Can survive adverse conditions of the gut

Can be resistant to poor sewage treatment

22
Q

What are features of enveloped viruses?

A

Environmentally labile
Disrupted by acid, detergent, drying and heat
Released from host cell by budding OR cell lysis
Must remain wet
Cannot survive in GI tract
Spreads in large droplets, body fluids (blood, saliva, breast milk, transplants, blood transfusion)
Does not necessarily need to kill the cell to spread

23
Q

What are latent viral infections?

A

Persistent infections
Virus does not reproduce hence no clinical symptoms
Virus can occasionally activate and produce symptoms

E.g. Herpes, chickenpox, HIV

24
Q

What are oncogenes viruses.

A

Viruses which cause cancer by activating pro-oncogenes

E.g. Epstein-Barr virus (Burkitt’s lymphoma)
Human Papillomaviruses (cervical cancer)
Human Herpesvirus 8 (Karposi sarcoma, common in AIDS

25
Q

What are the methods of viral transmission? give examples

A

Aerosols: influenza, picornavirus
Food/water: enteric viruses like reovirus, hepatitis A
Formites (tissues, clothes): rhinovirus
Direct contact with secretion (saliva, semen): cytomegalovirus
Sexual contact: herpes simplex virus, papilloma virus
Maternal-neonatal: rubella virus, herpes simplex virus
Blood transfusion/organ transplant: hepatitis B, HIV
Zoonoses (animals, insects,): influenza virus, rabies virus

26
Q

What is the progression of viral disease?

A
  1. Acquisition - entry into the body
  2. Initiation of infection - at primary site
  3. Incubation period - virus amplifies and spreads
  4. Replication in target tissue - disease symptoms
  5. Virus production in tissue, release, contagion
  6. Resolution or persistent infection/chronic disease
27
Q

What happens in herpes

A

A latent infection in neurons
Integrated in genome
Activated by fever, stress, sunlight
Causes cold sores

28
Q

What happens in chickenpox virus?

A

Resurfaces when immune system is wakened by disease or old age

Causes shingles

29
Q

What happens in HIV?

A

Latent in t called and macrophages
Integrated within genome
Causes AIDS

30
Q

What are the 6 steps of virus and phage replication?

A

Attachment, penetration, uncoating, biosynthesis, assembly, release

31
Q

What is the process of viral replication

A 
Binding to receptor on host cell
Entire virus enters cell
Viral genome escapes from capsid
Viral parts assembled
Viral escapes by cell lysis or budding
32
Q

Describe phage replication

A 
Binding to receptor in bacterial cell 
Injection of DNA into cell
Phage genes expressed , genome replicated 
Phage parts assembled
Phage escapes by cell lysis
33
Q

What are viroids and prions relative to viruses?

A

They are even smaller and less complex

34
Q

What are viroids

A

Short naked fragments of single stranded RNA

Infects plants

35
Q

What are prions

A

Small infectious proteins
Cause neurological diseases

E.g. Scrapie from sheep
Bovine spongiform encephalopathy - mad cow disease
Creutzfeld-Jakob disease (CJD, humans)

36
Q

Why is antiviral treatment used?

A

Antibiotics are only effect against living organisms

Viruses are not living

37
Q

How do antiviral treatments work?

A

They are limited to certain families

Hence resistance to antiviral drugs are becoming an ongoing problem

Nancymedsci202 (10 decks)

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