Brainscape's Knowledge GenomeTM

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


See full index

Virology > Virology Exam 1 > Flashcards

Virology Exam 1 Flashcards

1
Q

One enzyme that must be encoded by almost all viruses with RNA genomes is…

A

RNA polymerases using RNA as template

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

minus strand of viral RNA is one in which

A

is complementary to mRNA

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

who inserts viral proteins into a vesicle membrane

A

animal cells

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

what type of virus genome that most resembles cellular mRNA

A

single strand, positive strand mRNA

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

which type of animal virus can enter cell by receptor-mediated endocytosis

A

either enveloped or unenveloped viruses

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

T7 phage DNA enters bacterial cell by mechanism involving

A

digestion of cell membrane by phage capsid proteins to allow only DNA to enter cell

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

late genes in T7 are transcribed when

A

viral RNA polymerase protein is made

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

phage RNA polymerase

A

makes primer for phage DNA replication

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

phage DNA polymerase

A

synthesizes phage DNA

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

host RNA polymerase

A

transcribes early phage genes

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

what feature do T7, T even phages and mycobacterium have in common?

A

double stranded DNA genome

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

which of the following promoters is blocked by cI protein

A

both PL and PR

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

what is the function of cos sites in the lambda phage genome

A

circularize the genome

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

virus replication cycle

A
  • binding of receptor on cell
  • entry and uncoating
  • early gene expression
  • replication of viral genome
  • late gene expression
  • assembly of visions
  • exit cell
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

icosahedral symmetry

A
  • 20 faces
  • 12 points
  • fivefold, threefold and twofold rotational axes
  • hexons and pentons
  • may require scaffolding proteins
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

virus envelopes

A
  • lipid bilayer and viral glycoproteins

- obtained by budding

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

most plant viruses and many viruses of vertebrates have what kind of genome

A

positive-strand RNA

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

all viruses with negative-strand RNA genomes have what?

A

helical nucleocapsids and some have fragmented genomes

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

viruses with double-stranded RNA genomes are characterized by what

A

fragmented genomes and capsids with icosahedral symmetry

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

viruses with reverse transcription step can have what kind of genome

A

DNA or RNA

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

name the 5 classifications

A
  • dsDNA
  • ssDNA
  • dsRNA
    • ssRNA
    • ssRNA
  • retrovirus + RNA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

dsDNA

A
  • carries DNA-dependent RNA polymerase to produce mRNA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

ssDNA

A
  • carries DNA-dependent DNA polymerase to create dsDNA

- carries DNA-dependent RNA polymerase to create mRNA from dsDNA

24
Q

dsRNA

A
  • carries RNA-dependent RNA polymerase to create mRNA
25
Q

+ ssRNA

A

is the same thing as mRNA

26
Q
  • ssRNA
A
  • carries RNA-dependent RNA polymerase to create +RNA or mRNA
27
Q

retrovirus + RNA

A
  • reverse transcription with RNA-dependent DNA polymerase to create ssDNA
  • uses DNA polymerase to create dsDNA
  • integrates into the cells DNA
  • then creates mRNA from the cells DNA
28
Q

fusion proteins

A

proteins in cell wall that undergo major conformational changes that lead to fusion

29
Q

what triggers passage of virus from endosome to the cytosol

A

pH

30
Q

what microtubules move the visions an dcapsids within the cell

A

dyenin and dynactin

31
Q

how can virus entry be prevented?

A
  • intercept virus before it reaches cell with neutralizing antibodies
  • flood extracellular space with soluble receptor
  • block cellular receptor
  • inhibit membrane fusion
  • inhibit uncoating
32
Q

entry of virus into a cell occurs by what mechanism?

A
  • fusion
  • receptor-mediated endocytosis
  • passage of virion genome through a pore
33
Q

podovirus

A

has tail that is short

34
Q

myovirus

A

contains a contractile tail

35
Q

siphovirus

A

has long, flexible tail

36
Q

T7 virus/genome

A
  • linear dsDNA
  • terminal direct repeated sequence
  • early, middle and late genes
  • RNA polymerase immediately begins transcribing as the DNA enters cell
  • makes own polymerase
  • concatemers
  • can ONLY BE LYTIC
37
Q

early genes

A

control expression of phage gene

38
Q

middle genes

A

control phage DNA replication

39
Q

late genes

A

code for structural proteins

40
Q

concatemers

A
  • terminal repeated sequence in T7 genomes
  • solves problem of losing sequences at end of DNA during replication
  • only 1 genome fills a head, or one concatemer
41
Q

T7 entry into the cell

A
  • DNA is injected by tail
  • DNA is spooled in by cellular RNA polymerase
  • DNA is spooled in by T7 RNA polymerase
42
Q

what is the one-step growth curve

A

how long it takes for virus to replicate and lyse the cell

43
Q

eclipse stage

A

phages in cell, but haven’t been released

44
Q

latent stage

A

phages have been released from cell

45
Q

maturation stage

A

time to when you have first completely assembled phage until phages are first released

46
Q

lambda phage

A
  • also referred to as temperate

- can be lytic or lysogenic

47
Q

prophage

A

bacterial DNA that contains integrated DNA from the phage

48
Q

virion of lambda phage

A
  • head is naked icosahedral capsid (T=7)
  • flexible, tube shaped tail
  • terminal fibers
49
Q

lambda phage genome

A
  • linear dsDNA but circulizes once in the cell
  • ends are cohesive-sticky ends (cos sequences)
  • codes for 60 proteins
  • transcribed by cellular RNA polymerase
  • genes grouped by function
  • immediate early, early and late genes
  • repressors, antiterminators and activators present
50
Q

types of repressors

A

cro and cI

51
Q

cro

A

promotes lytic behavior

- suppresses cI synthesis and regulates early gene transcription

52
Q

cI

A

promotes lysogenic behavior

- blocks expression of lytic program by regulating PL, PR and PRM

53
Q

operator

A

site at which the repressor binds

54
Q

PRM

A

maintains transcription of cI

55
Q

PR

A

maintains transcription of cro

56
Q

induction

A
  • leads to lytic replication

- cleavage of cI repressor in cells with damaged DNA lead to this

57
Q

lambda DNA replication

A
  • rolls circular DNA into concatemer with cos sites

- cos sites are where the cutting sites are (by terminus), only one cos site to cos site goes into a virus

Virology (6 decks)

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