Brainscape's Knowledge GenomeTM

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


See full index

IIH > Viruses > Flashcards

Viruses Flashcards

1
Q

List the classification criteria for viruses.

A

1 - Single stranded or double stranded genome.

2 - RNA or DNA.

3 - Sense or antisense.

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

Define viroid.

A

Plant pathogens formed of small, rod-like RNA molecules.

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

Define prion.

A

Pathogenic proteins that affect protein folding.

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

List 3 properties of prions that make them difficult to treat.

What gives prions these properties?

A

1 - They are resistant to heat inactivation.

2 - They are resistant to radiation damage.

3 - They are resistant to DNAse RNAse treatment.

  • Prions have these properties as they contain no nucleic acid.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Why are viruses unable to undergo mitosis independently?

A

Because they contain no organelles.

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

List the 7 groups of viruses.

A

1 - Double stranded DNA viruses.

2 - Single stranded DNA viruses.

3 - Double stranded RNA viruses.

4 - Sense RNA viruses.

5 - Antisense RNA viruses.

6 - RNA reverse transcribing viruses.

7 - DNA reverse transcribing viruses.

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

Give an example of a double stranded DNA virus.

A

Herpes virus family.

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

Give an example of a single stranded DNA virus.

A

Parvovirus.

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

Give an example of a double stranded RNA virus.

A

Rotaviruses.

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

List 3 examples of sense RNA viruses.

A

1 - Polio.

2 - HCV.

3 - FMDV.

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

List 2 examples of antisense RNA viruses.

A

1 - Influenza

2 - Ebola.

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

Give an example of an RNA reverse transcribing virus.

A

HIV.

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

Give an example of a DNA reverse transcribing virus.

A

HBV.

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

Define virion.

A

The infectious stage of the virus lifecycle.

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

Define capsid.

A

The protein coat of a virus that surrounds the nucleic acid.

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

What is Baltimore classification?

What is the advantage of this classification system?

A

A system of classifying viruses based on their genome.

The advantage is that the behaviour of viruses of the same group can be predicted.

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

List the stages of the viral life cycle of a sense RNA virus.

A

1 - Entry.

2 - Disassembly.

3 - Replication of genomes.

4 - Assembly of genomes.

5 - Release of multiple viruses.

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

How do RNA retroviruses produce DNA that can be integrated into the host cell?

A

By making a reverse transcript of their RNA.

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

List the 3 phases of viral growth.

A

1 - Eclipse phase.

2 - Log phase.

3 - Plateau.

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

What does the eclipse phase of viral growth represent?

A

The virus adsorbing onto cells and beginning to utilise the host cell’s apparatus.

21
Q

What does the plateau phase of viral growth represent?

A

The end of replication (further growth will occur, but will not be shown on a one-step growth phase).

22
Q

How do viruses that replicate by lytic infection differ visually from other viruses?

A
  • Viruses that replicate by lytic infection tend to be naked particles (capsids with spikes).
  • Viruses that bud chronically from infected cells tend to pick up a membrane as they leave, so are called ‘enveloped’.
23
Q

Define tropism.

A

The property of a virus to infect cells by binding to a specific surface receptor.

24
Q

Describe the tropism of HIV.

A

HIV binds to:

1 - CD4 cell surface receptors.

2 - CCR5 cell surface receptors.

25
Q

List 2 cells that can be infected by the HIV virus.

A

1 - Macrophages.

2 - CD4+T cells.

26
Q

What is the name of the pattern of diseases associated with HIV?

A

Autoimmune deficiency syndrome (AIDS).

27
Q

How many times does the chemokine receptor cross the cell surface membrane?

A

7.

28
Q

How does the CDR5-delta 32 mutation give immunity to HIV?

A

The mutation results in a smaller CCR-5 receptor that lies intracellularly rather than on the cell surface.

29
Q

Define zoonosis.

Give an example of a zoonosis.

A
  • An infectious disease caused by bacteria, viruses or parasites that spreads between species.
  • E.g. ebola.
30
Q

What is the cause of antigenic variation in influenza?

A

Influenza is able to undergo genetic reassortment.

31
Q

List 2 important proteins of the flu virion surface.

A

1 - Haemagglutinin.

2 - Neuraminidase.

32
Q

What is the function of haemagglutinin?

A

A protein responsible for haemagglutination.

33
Q

Explain why domestication of animals increases the risk of viral infection.

A
  • Different species carry different strains of viruses.
  • Domesticating different species may lead to reassortment between the different strains.
  • New strains can be created.
34
Q

List 2 examples of targets for antiviral medications.

A

1 - Blocking the cell surface receptors to which viruses bind.

2 - Interfering with intracellular replication of the virus.

35
Q

Define virally encoded host cell shutoff (VEHCS).

A

The production of viral proteins which prevent host gene expression by blocking host transcription, suppressing mRNAs or translation.

36
Q

How does polio induce virally encoded host cell shutoff?

A
  • Normally, translation is initiated when ribosomes bind to the m7G cap of the mRNA via the cap binding complex.
  • The poliovirus produces a protein known as protein 2A, which cleaves the cap binding complex.
37
Q

How is polio able to carry out translation if it expresses protein 2A?

A

Polio’s genome contains an internal ribosome entry site (IRES), which doesn’t require a cap-binding complex for translation to occur.

38
Q

What is eIF4G?

A

A component of the eIF4F cap binding complex which acts as the bridge between the m7G cap of the mRNA and the 40S ribosome unit.

39
Q

How does HSV evade the immune response?

A
  • When HSV infects a cell, it incorporates its genome into the nucleus of the host cell but does not produce proteins (it is quiescent).
  • The virus instead produces mRNA transcripts called latency associated transcripts (LATs).
  • The immune recognition requires production of proteins, however the latent HSV doesn’t make any.
40
Q

What do LATs produce?

What is the function of this product?

A

Micro RNAs, which act to control the host cell.

41
Q

What is the advantage of a virus incorporating its genome into the nuclei of gametes?

Which viruses do this?

A
  • The products of their genome will be recognised as self in the second generation.
  • These viruses are known as human endogenous retroviruses (HERVs).
42
Q

List 3 viruses that cause acute infection.

A

1 - Rhinovirus.

2 - Rotavirus.

3 - Influenza virus.

43
Q

Give an example of a virus that causes persistent infection.

A

Lymphocytic choriomeningitis virus.

44
Q

Give an example of a virus that causes persistent, latent infection.

A

Herpes simplex virus.

45
Q

List 3 viruses that cause persistent, slow infection.

A

1 - Measles virus.

2 - HIV.

3 - Human T-lymphotropic virus.

46
Q

What causes most of the common symptoms of viral infection?

A

The general effects of the innate immune response.

47
Q

Define interferon.

A

A group of signalling proteins made and released by host cells in response to the presence of viruses.

48
Q

How does interferon bring about changes in nearby cells?

A

By stimulating the expression of interferon stimulating genes (ISGs), increasing antiviral defences.

IIH (26 decks)

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