Brainscape's Knowledge GenomeTM

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


See full index

D2 Summer > Microbio Week 9 - How Viruses Replicate and Change (Exam 3) > Flashcards

Microbio Week 9 - How Viruses Replicate and Change (Exam 3) Flashcards

1
Q

Are viruses good targets for antivirals?

A

NO

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

What do viruses use for replication?

A

Host cellular products

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

Name the steps of replication

A
  1. Attachment
  2. Tropism
  3. Entry
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How does a virus attach?

A

Bind to cellular receptors on host cell

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

If a cell does not have the viral receptor, the virus cannot do what?

A

Infect the cell

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

What helps determine what cells the virus can infect (aka the tropism of the virus)?

A

The viral receptor

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

T/F: There are other determinants of tropism other than receptors. For example, some viruses can enter certain cells, but if the cells are missing a cellular factor required for viral replication, the virus will not be able to replicate

A

True

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

What determines not only what cell type the virus infects but also the species of animal it can infect?

A

Tropism

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

What type of transmission is tropism important in?

A

Zoonotic

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

Entry at the cell membrane is mainly used for what type of viruses?

A

Enveloped

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

Some enveloped viruses can fuse the lipid bilayer of the virus with what?

A

The cell membrane

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

Both enveloped and naked viruses can be ___________

A

endocytosed

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

What helps the virus enter the cytoplasm from the endosome?

A

Lower pH of the endosome

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

Where does most DNA virus replication occur?

A

Nucleus

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

Where does DNA virus replication occur for poxvirus? (exception)

A

Cytoplasm

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

Where does DNA virus replication occur for HBV? (exception)

A

Nucleus + cytoplasm

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

What are the 3 DNA viruses that do NOT make their own viral DNA polymerase?

A

Papillomavirus
Polyomavirus
Parvovirus

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

What do Papillomavirus, Polyomavirus, and Parvovirus use to replicate their viral DNA?

A

Cellular DNA polymerase

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

What phase of the cell cycle must the cells be in for Papillomavirus, Polyomavirus, and Parvovirus to replicate their viral DNA?

A

S-phase

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

Papillomavirus and polyomavirus can cause cell-cycle ____________ by inhibiting pRb and making the cell go into cycle.

However, if the virus causes cell cycle dysregulation but does not kill the cell, there is a chance for the cell to become ______________

A

dysregulation; cancerous

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

Which virus (papilloma, polyoma, or parvo) cannot cause the cell to enter the S-phase and must infect cells already replicating?

A

Parvovirus

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

What do poxviruses have to make mRNA?

A

DNA-dependent RNA polymerase

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

What does HBV have?

A

Reverse transcriptase

24
Q

mRNA is the same as what?

A

+ssRNA

25
Q

When +ssRNA viruses enter the cell, what can they do right away?

A

Make protein

26
Q

the first thing +ssRNA viruses do when they enter the cell is use the cellular machinery to translate their +ssRNA into a large polyprotein.

What is the exception?

A

Retroviruses

27
Q

+ssRNA must cleave the large polyprotein they make into what individual viral __________. This means all +ssRNA viruses have what?

A

proteins; viral protease

28
Q

T/F: All RNA viruses must make a viral RNA-dependent RNA polymerase

A

True!

29
Q

What 2 things do all +ssRNA viruses have that are excellent targets for antiviral drugs?

A

Viral protease + polymerase

30
Q

Retroviruses are +ssRNA viruses with how many copies of the same genetic material?

A

2

31
Q

Which virus is diploid?

A

Retrovirus

32
Q

Why are retroviruses unique?

A

Make a DNA copy of themselves using reverse transcriptase as part of their replication cycle

33
Q

T/F: The reverse transcriptase used by retroviruses is carried into the cell; it is in the virion

A

True

34
Q

Once retroviruses make a DNA copy of their genetic material, they integrate that copy into the host cell chromosome.

How long is that viral DNA copy in the cell?

A

For the life of the cell

35
Q

Retroviruses use the cellular RNA polymerase to make viral ________ from the integrated viral DNA. This mRNA travels to the ___________, where it is made into _____________

A

mRNA; cytoplasm; protein

36
Q

In HIV (a retrovirus), when does the viral protease cleave the viral proteins?

A

After budding of the virion

37
Q

What helps mature viral particles from retroviruses?

A

Protease

38
Q

What is the first thing -ssRNA viruses do when they enter the cell?

A

Make mRNA from their -ssRNA

39
Q

How do -ssRNA viruses make mRNA from their -ssRNA?

A

Use a viral polymerase that goes into the cell with them in their virion

40
Q

Do -ssRNA viruses need a protease?

A

NO - they make mRNA for each viral protein

41
Q

Which virus is a “defective” virus that must co-infect a cell with HBV in order to replicate?

A

Hep D virus

42
Q

What is this describing?

2 viruses of the same type infect the same cell. They might switch parts of their genome by recombination, which can result in several proteins being replaced at a time between the strains, resulting in a large change

A

Gene recombination

43
Q

What is needed for gene reassortment?

A

Segmented genome

44
Q

Which family of viruses have segmented genomes?

A

BOAR viruses

(bunya, orthomyxo, arena, reo)

45
Q

What is it called when two strains of the same segmented virus infect the same cell?

A

Reassortment

46
Q

What is this describing?

The resulting viruses have segments from both
infecting stains, resulting in a very different virus from the parental strains

A

Reassortment

47
Q

What is responsible for the majority of influenza pandemics?

A

Reassortment

48
Q

2 examples of antigenic shift (large changes)

A

Recombination
Reassortment

49
Q

Example of antigenic drift (small changes)

A

Mutation

50
Q

Different polymerases have different _________; they have different error rates and ability to correct mistakes

A

fidelity

51
Q

Rank the following from lowest to highest mutation rate:

DNA viruses
RNA viruses
Higher eukaryotes
Prokaryotes

A

Higher eukaryotes < Prokaryotes <DNA
viruses< RNA viruses (highest mutation rate)

52
Q

T/F: A base inserted by mistake will not be corrected by RNA viruses, leading to a higher mutation rate

A

True

53
Q

Most RNA viruses cannot do what?

A

Proofread

54
Q

T/F: It is possible in chronic infections, when antiviral therapy is started, a virus carrying a mutation resistant to the antiviral is already present. This can be true for HIV and HCV, which is why combination therapy is so necessary

A

True

55
Q

If you have a chronic infection, which
allows the virus to replicate many times, you could have lots of different viruses in the body at any one time (HIV and HCV) or put another way, many _______________ of the virus

A

quasi-species

56
Q

What helps viruses change rapidly with changing environmental conditions?

A

Making single nucleotide changes every 1-100 viruses produced

D2 Summer (37 decks)

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