Brainscape's Knowledge GenomeTM

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


See full index

BIO 246: Microbiology of Human Disease > Ch 5: Viruses > Flashcards

Ch 5: Viruses Flashcards

You may prefer our related Brainscape-certified flashcards:
Biology 101 flashcards
1
Q

What are viruses?

A

acellular infectious particles and obligate intracellular parasites

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

Viruses are composed of biological molecules, e.g. nucleic acids, proteins, but not …

A

Cells

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

Order from smallest to largest

Yeast, virus, bacteria

A

virus, bacteria, yeast

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

What do all viruses have? What do only some viruses have?

Structure

A

All viruses have a NUCLEIC ACID GENOME
- genes for viral reproduction

PROTEIN CAPSID
- protective coat for transport of genes and attachment to
host cells

Some viruses have a LIPID ENVELOPE
- a phospholipid bilayer with spike proteins for attachment
to host cell

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

What are the features of the viral capsid?

A

made of protein subunits called capsomers

may have capsid spikes for attachment to host cells
helical or polyhedral

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

What are the features of the viral envelope?

A

stolen from host cell membrane by viral budding

phospholipid bilayer with viral “spike” glycoproteins

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

What is the viral genome composed of?

A

DNA or RNA

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

How are viruses classified by:

  • Genome
  • Capsid
  • Envelope
A
  • Genome: DNA or RNA
  • Capsid: Helical or Polyhedral
  • Envelope: Naked or Enveloped
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What is a virus that infects bacteria?

A

bacteriophage

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

What are the steps of viral replication?

A
  1. Adsorption
  2. Penetration & Uncoating
  3. Synthesis
  4. Assembly
  5. Release
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the step of the viral replication cycle, adsorption?

A

Attachment

tropism defines the host-cell specificity of a virus

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

What are the methods of Penetration & Uncoating?

A

Endocytosis and Fusion

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

What must be synthesized during viral replication?

A

NUCLEIC ACID SYNTHESIS
- make copies of viral genome

PROTEIN SYNTHESIS
 - make viral enzymes
 - make viral capsomers
 - make viral envelope spikes and insert in host 
    membrane
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

How do bacteriophages introduce their DNA into host?

A

Injection

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

What types of virus can enter the cell via endocytosis?

A

Enveloped virus and Naked Virus

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

What is the tropism of HIV?

A

CD4 T Helper Cells

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

How can Host Cells help w/ synthesis?

A

All cells have three enzymes and can perform…

CELLULAR REPRODUCTION
DNA → DNA x 2 (replication)
DNA polymerase

GENE EXPRESSION
DNA → RNA (transcription)
(DNA-dependent) RNA polymerase
mRNA → protein (translation)
ribosomes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is the Normal Flow of Genetic Information in Cells?

A

DNA →mRNA using RNA Polymerase
mRNA →Proteins using ribosome

DNA →DNA using DNA Polymerase

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

What three things can a host cell do with DNA? (This is the flow of genetic information in cells)

A
  • replication using DNA polymerase
  • transcription using RNA Polymerase
  • translation using Ribosomes
20
Q

How does a DNA virus use host cell enzymes?

A

COPYING VIRAL DNA (vDNA) GENOME
vDNA → vDNA x 2 using DNA polymerase (host)

EXPRESSION OF VIRAL GENES
vDNA → vRNA using DNA-dependent RNA polymerase (host)
vRNA → vProtein using ribosomes (host)

vProtein + vDNA = New Virion

21
Q

Walk through the types synthesis a DNA virus can perform.

A

vDNA

22
Q

How does a DNA virus use host cell enzymes?

A

COPYING VIRAL DNA (vDNA) GENOME
vDNA → vDNA x 2 using DNA polymerase (host)

EXPRESSION OF VIRAL GENES
vDNA → vRNA using DNA-dependent RNA polymerase (host)
vRNA → vProtein using ribosomes (host)

vProtein + vDNA + assembly = New DNA Virions

23
Q

How is the synthesis of RNA Viruses different that DNA Viruses?

A

RNA viruses require a viral enzyme, RNA Dependent RNA Polymerase, because host cells cannot make copies of RNA from a RNA template (no host enzyme)

24
Q

How is the synthesis of RNA Viruses different that DNA Viruses?

A

RNA viruses require a viral enzyme, RNA Dependent RNA Polymerase, because host cells cannot make copies of RNA from a RNA template (no host enzyme)

25
Q

How does an RNA Virus synthesize necessary components to replicate?

A

copying of viral RNA genome
- vRNA → vRNA x 2 using RNA-dependent RNA
polymerase (viral)

expression of viral genes
- vRNA → vProtein using ribosomes (host)

vRNA + vProtein + assembly = new RNA Virions

26
Q

How is synthesis of RNA Retroviruses different from RNA viruses?

A

RNA retroviruses require a viral enzyme, Reverse Transcriptase, but the enzyme does not directly synthesize RNA; it makes DNA instead

27
Q

How does an RNA Retrovirus synthesize necessary components to replicate?

A

copying of viral NA genome into DNA
- vRNA → vDNA using reverse transcriptase (viral)

copying of viral DNA genome into RNA
- vDNA → vRNA using DNA-dependent RNA polymerase
(host)

expression of viral genes
- vRNA → vProtein using ribosomes (host)

vRNA + vProtein + Assembly = New RNA Retrovirions

28
Q

What does it mean that RNA Viruses have “Low Fidelity”?

A

error prone = high mutation rate

fidelity = ability to copy accurately every time

29
Q

How do some viruses incorporate their genomes into the host chromosome?

A

integration
- HIV uses an enzyme called integrase to recombine the
viral DNA copy into a host chromosome
- latency = virus is dormant (host is unaware of infection)

lysogeny
- bacteriophage → prophage

30
Q

Which host enzyme is used by all viruses?

A

Ribosomes

31
Q

Which HIV enzyme promotes viral latency?

A

Integrase

32
Q

How are viruses released from host cells?

A

Naked viruses = lysis

Enveloped viruses = budding (takes host membrane w/ it to form new envelope)
- can insert spikes into host membrane before leaving

33
Q

What occurs during the step of viral replication called assembly?

A

capsomers coat copies of viral DNA or RNA to form capsid

envelope spike proteins are inserted in the host membrane

34
Q

What enzyme does HIV require for assembly?

A

Protease processes proteins made by virus before assembly

35
Q

What are the enzymes necessary for HIV replication?

A

Reverse Transcriptase
Integrase
Protease

These are targeted by HIV Antivirals

36
Q

You can’t culture viruses by giving them nutritive cell media. How can you do it? How do you know it’s working?

A

Have to “feed” viruses cells

Grow viruses on other cells. You know it’s working when you see viral plaques (cell lysis) on culture

37
Q

What do bacteriophages do?

A

viruses that infect bacteria.

- kill bacteria cells thorugh lysis

38
Q

What is phage therapy?

A

using bacteriophages to kill harmful bacteria

39
Q

What additional problems to cells, outside of killing them, can viruses cause?

A

Cytopathic effects like latent state (HSV)

40
Q

What are oncoviruses?

A

cancer causing viruses that transform cells

HPV → genital warts → cervical cancer
hepatitis virus → hepatitis → liver cancer

41
Q

How do we treat viral infections?

A

vaccines (against some viruses, e.g. MMR)

antibiotics do not affect viruses

limited antiviral agents (very specific to each virus)

interferons

42
Q

Enveloped viruses are released from host cells by a process called:

A

Budding

43
Q

What type of virus is associated with cell transformation and cancer?

A

oncovirus

44
Q

What are prions?

A

non-viral infectious agents
- defective (misfolded) neural proteins
- reproduce w/o genes through conversion (misfold other
neighboring proteins)

45
Q

Prions are infectious _______ proteins.

A

neural

46
Q

Prions do not have genes so they reproduce by a process called:

A

conversion

47
Q

Prions cause transmissible spongiform encephalopathies. How is it transmitted?

A

Cow w/ Bovine Spongiform Encephalopathy (mad cow disease) is slaughtered and the meat is eaten

BIO 246: Microbiology of Human Disease (22 decks)

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