Week8C1-C2 : Taxonomy viruses Flashcards

1
Q

Viruses are grouped into families that end with ____

A

viridae

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2
Q

Virueses are given a genus name that end with ___

A

virus

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3
Q

Viruses are given a species name that is in ____

A

english

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4
Q

The ____ configuration of RNA genome can be translated directly

A

plus

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5
Q

The minus strand ssRNA genome needs to be ___ before it can be translated

A

transcribed

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6
Q

How many classes is there in the baltimore classification scheme

A

7 classes

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7
Q

The baltimore classification scheme is a classification based on ____

A

type of genome

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8
Q

what are the steps in the life cycle of a virus?

A
  1. adsorption
  2. penetration
  3. uncoating
  4. replication
  5. maturation
  6. release
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9
Q

What is viropexis ?

A

the endocytosis of a virus by the host cell

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10
Q

What are the three ways viruses can enter the host cell?

A
  1. direct penetration (everything left outside)
  2. membrane fusion (enveloped viruses, the envelope is left at surface)
  3. viropexis (most enveloped viruses of eukaryote, eveything enters)
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11
Q

T or F : in enveloped viruses, the capsid may be left at the surface

A

false, the capsid is left at the surface only for naked viruses

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12
Q

The lamba and T4 have a ____ genome

A

double stranded DNA

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13
Q

The øX174 has a _____ genome

A

single-stranded DNA genome (+)

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14
Q

The MS2 has a _____ genome

A

single stranded RNA genome (+)

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15
Q

What are the two periods of virus replication

A
  1. latent period

2. release (rise) period

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16
Q

What are the two stages of the latent period ?

A
  1. eclipse

2. maturation

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17
Q

What is the burst size?

A

number of virions released

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18
Q

What is the eclipse?

A

time necessary for the host cells to replicated the viral genome and to synthesize the viral components

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19
Q

What is the maturation perido?

A

time needed for the different components to be assembled

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20
Q

The ø6 has a _____ genome

A

double stranded RNA genome

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21
Q

Most phages contain ____ genomes

A

dsDNA linear

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22
Q

What is a phage?

A

a viruse that attacks the bacteria

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23
Q

What are the two types of bacteriophages?

A
  1. virulent phages

2. temperate phages

24
Q

_____ phages always leads to the lysis of host cells

A

virulent

25
Q

____ phages have two options, ____ pathway or ___ pathway

A

temperate
lytic
lysogenic

26
Q

Lamba is a ___ phage

A

temperate

27
Q

the bacteriophage T4 recognize the ____ on the membrane

A

LPS

28
Q

Bacteriophage T4 is a ___ phage

A

virulent

29
Q

Viruse replication takes ___ minutes in the case of bacterial viruses

A

25-30

30
Q

Viruse replication takes ___ hours in the case of animal viruses

A

8-40h

31
Q

What is a lysogen ?

A

bacteria that contains a prophage

32
Q

What is a prophage?

A

viral DNA incorporated into the host genome

33
Q

where is intergrated the viral DNA in the bacrerial DNA

A

at the att-lambda site

34
Q

What is the enzyme that catalyse the entry of the viral DNA into the bacterial host genome

A

lambda integrase

35
Q

The region ____ is complementary to the cut region in the temperate phage genome

A

COS

36
Q

What are the steps in the single-stranded DNA (+) phage infection

A
  1. the minus DNA strand must be synthesized
  2. From the - DNA strand, mRNA (+) is made and then translated
  3. Replication of the genome by rolling circle
  4. gives one replicative dsDNA form and one ssDNA (+) strand
  5. The dsDNA can make another replicative form
37
Q

What are the steps in the single-stranded RNA (+) phage infection

A
  1. the + strand is used for translation to make viral proteins and RNA replicase
  2. RNA replicase (RNA dependant RNA polymerase) synthesize the - strand.
  3. The - strand is used to make more + strand ssRNA.
38
Q

The genomes of ___ viruses will usually be replicated in the nucleus of the cell.

A

DNA viruses

39
Q

The genomes of ___ viruses will usually be replicated in the cytoplasm of the cell.

A

RNA viruses

40
Q

What are the steps in the double-stranded DNA phage infection

A
  1. the double stand is used to make mRNA
  2. The mRNA is used to make early, delayed and late proteins
  3. rolling circle replication produces new ds-DNA
41
Q

What are the steps in the single-stranded DNA (+) phage infection in the case of polio?

A
  1. the + strand is used for the synthesis of a large polyprotein
  2. the large protein is cleaved into smaller proteins (structural proteins, proteases, RNA replicase)
  3. RNA replicase is used to make a - strand from the plus strand
  4. the - strand is used has a template to make more + strands
42
Q

What is the purpose of the protease in the polio virus

A

cleave the large polyprotein

43
Q

What are the steps in the single-stranded RNA (-) phage infection

A
  1. the - strand is first transcribed into a + strand by the RNA polymerase that comes inside the virus
  2. the + strand is used to make proteins and RNA polymerase
  3. The + strand is used to make more - strands
44
Q

Measle is an example of ____ genome

A

minus ssRNA

45
Q

Polio is an example of ___ genome

A

plus ssRNA

46
Q

What are the steps in the double-stranded RNA phage infection

A
  1. the minus strand is used to make + strands

2. the + strand is translated to proteins and used to make more - strands

47
Q

HIV is an example of ____ virus

A

retro

48
Q

The virion of HIV carries :

A
  1. reverse transcriptase
  2. two copies of ssRNA (+)
  3. integrase
  4. proteases
49
Q

What are the steps in the retrovirus phage infection

A
  1. the reverse transcriptase carried by the virion reverse the transcription of + ssRNA into DNA
  2. DNA travels to the nucleus and is incorporated into the host genome
  3. the provirus in the host DNA is used ot make mRNA to make new virions
50
Q

What are the four different mechanisms by which viruses produces tumors

A
  1. transduction
  2. insertion of a strong promoter
  3. inactivation of a tumor supressor gene
  4. expression of a viral protein that induces transformation
51
Q

What are the type of virus that can cause transduction

A

RNA viruses

52
Q

What are the type of virus that can cause insertion of a strong promoter

A

retroviruses (insertion of LTR)

53
Q

What are the type of virus that can cause inactivation of tumor supressor gene

A

retroviruses (insertion of LTR)

54
Q

What are the type of virus that can cause expression of viral protein

A

DNA viruses

55
Q

What are the genes of HPV that induces transformation of the cells

A

E6 and E5 genes