Brainscape's Knowledge GenomeTM

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


See full index

Supplemental Micro > RNA Viruses > Flashcards

RNA Viruses Flashcards

1
Q

why is the next supervirus expected to be an RNA virus?

A

because they have high mutation rates that cause antiviral resistance and barrier to vaccines

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

what are some common features of RNA viruses

A

RNA is genetic material and template for protein synthesis, dual purpose of replication to copy genome and make mRNA

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

what is the difference between transcription and replication in RNA viruses?

A

transcription is mRNA synthesis, replication is RNA genome synthesis

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

what are the types of genomes and what do they mean?

A

dsRNA, + ssRNA and -ssRNA
positive strand is the sense strand and the same as mRNA
negative strand is the nonsense strand and the mRNA template

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

what is the extra step of + ssRNA replication and why does it occur?

A

a negative strand (template strand) must be made to amplify the genome and mRNA

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

what is RDRP and whose genome does it come from?

A

it is a RNA dependant RNA polymerase that comes from the viral genome (humans cannot perform this function)

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

where in the cell does RDRP act and why?

A

in the cytoplasm on cell membranes to concentrate components and increase efficiency

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

why are there more mutations in RNA viruses compared to DNA viruses and how does this change the intracellular environment?

A

RDRP does not proofread so there is a high error rate. this means a single cell has a mixture of wild types and mutants

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

what is recombination in viruses and what is the product?

A

similar to human recombination with large segment exchange, creates hybrid viruses that may have new features

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

what is reassortment in respect to RNA viruses?

A

segmented RNA viruses can mix their segments when infected with multiple strains. leads to new variants

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

what is a quasispecies?

A

a “sort of species” with a large amount of diversity among each type of virus

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

what type of genome does Poliovirus have?

A

+ ssRNA

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

what does poliovirus infect and how does it spread?

A

infects GI tract first and may spread to muscles and neurons by acquiring mutations

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

what is the reservoir and transmission of poliovirus?

A

persists in water and infects humans by fecal-oral rout

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

do all people who contract poliovirus have infection of motor neurons?

A

95% of people only have GI symptoms. Neurons involved with 1% of the 5% of people who have disseminated diesase

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

when does RNA synthesis switch from mRNA synthesis to genome synthesis in Poliovirus?

A

when capsid proteins accumulate

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

why is there little collision between RDRP and ribosomes in Poliovirus?

A

because translation happens first (RDRP scarce) and then - RNA synthesis occurs later

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

what type of vaccine is there for poliovirus?

A

live attenuated vaccine or killed virus

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

how does poliovirus enter the cell?

A

it interacts with multiple receptors on the cell surface and is endoxytosed. The virion is uncoated in the endosome and injects the genetic material into the cytoplasm by becoming hydrophobic

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

how and when is Poliovirus translated?

A

Translation occurs before RDRP makes the negative sense strand by ribosomes. The polyprotein is then cleaved.

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

what is the main clinical presentation of rotavirus?

A

profuse diarrhea, dehydration and maladsorption. peak incidence in winter

22
Q

what is the classification of rotavirus?

A

reovirus, dsRNA, segmented, naked icosahedron

23
Q

what is the classification of influenza?

A

orthomyxovirus - ssRNA, segmented, enveloped helical

24
Q

what is the classification of HIV?

A

retrovirus +ssRNA 2 copies, enveloped icosahedron

25
Q

is RDRP included in the rotavirus packaged in the virion?

A

yes, it is a -ssRNA virus

26
Q

Where does transcription and translation occur in rotavirus?

A

transcription occurs within the loosened capsid and translation occurs in the cytoplasm

27
Q

after assembly in the virus, what is the progression of rotavirus out of the cell?

A

virions bud into the rough ER and are either exocytosed by vesicles or lyse the cell during egress

28
Q

what event happens to rotavirus after it exits the cell?

A

virions mature in the gut lumen

29
Q

what is the treatment for rotavirus?

A

oral rehydration (make sure they are not contaminated)

30
Q

is there a vaccine for rotavirus?

A

yes, a live attenuated vaccine

31
Q

what are the symptoms of uncomplicated infuenza?

A

upper/lower respiratory tract involvement, muscle aches, fever, headaches and weakness

32
Q

what are some complications that can be caused by influenza?

A

primary viral or secondary bacterial pneumonia (or mixture) or rhabdomyelitis (muscle breakdown)

33
Q

where does transcription and replication of influenza occur?

A

inside the nucleus

34
Q

how does influenza egress from the cell?

A

it buds off and is cleaved from surface receptors by neuraminidase to release into respiratory droplets

35
Q

describe the genome of influenza

A

-ssRNA genome that is segmented into 8 portions

36
Q

what are the two types of influenza vaccines?

A

fluzone (trivalent inactivated vaccine with two A subtypes and one B subtype) and flumist (live attenuated vaccine that is a mist)

37
Q

describe antigenic shift and antigenic drift as it refers to influenza

A

antigenic shift refers to segment mis-sorting while antigenic drift refers to random mutations

38
Q

what are three reasons that death rates due to HIV infection decreasing?

A

better treatments, hope for treatment to succeed and motivation for early diagnosis

39
Q

what are the stages of HIV disease?

A

exposure, acute (primary) infection, seroconversion, latent period, early symptomatic infection, AIDS, and advanced HIV infection

40
Q

what are the classifications of AIDS and advanced HIV infection?

A

AIDS- CD4 count<50 cells

41
Q

what is HIV’s host range and tropism?

A

humans

CD4 cells and macrophages

42
Q

what are the two mediators of HIV disease?

A

chronic immune activation and depletion of T cells and macrophages

43
Q

if a patient comes in presenting with esophageal candidiasis, what virus would you also test for?

A

HIV

44
Q

what is the first thing that HIV does when the virion fuses with the plasma membrane of a cell and uncoats?

A

Viral reverse transcriptase turns the + ssRNA into dsDNA in the cytoplasm. This is integrated into the host genome

45
Q

what is the RNA product of HIV’s integrated DNA used for and how is it transcribed?

A

it is both the mRNA for translation and the viral genomes that will be packaged. It is transcribed with host RNA pol 2

46
Q

how does HIV egress from the cell?

A

viral proteins and 2 copies of the genome bud from the cell.

47
Q

what happens to the HIV virion once it leaves the cell?

A

capsid proteins are cleaved to form the final shape

48
Q

why does HIV lie latent in the cell for a long time before replication?

A

when the T cell begins to divide, it supplies the virus with the necessary building blocks

49
Q

how is HIV diagnosed?

A

serologic tests for antibodies, nucleic acid assay for viral load (molecular diagnostics) and CD4 T cell count

50
Q

what are 4 ways to prevent HIV?

A

risk avoidance, community awareness, public health measures and chemoprophylaxis (antivirals0

51
Q

what is the treatment for HIV?

A

combination of at least 3 drugs (avoid resistance)

52
Q

what are 5 goals of HIV treatment?

A

suppress viral load, restore immune function, prevent transmission, prevent drug resistance and improve quality of life

Supplemental Micro (8 decks)

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