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BIO 1200 > Chapter 19: Genetics Of Viruses And Bacteria > Flashcards

Chapter 19: Genetics Of Viruses And Bacteria Flashcards

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Biology 101 flashcards
1
Q

viruses are __ particles because

A

nonliving
not composed of cells
don’t replicate by themselves
do not carry out metabolism

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2
Q

a virus or its genetic material must be taken up by a living cell to

A

replicate

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3
Q

viruses are smaller than
size

A

bacteria
virus 0.02-0.4um
bacteria 1-5 um
eukaryotic cell 40-60um

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4
Q

Virus Host Range

A

Broad host range: can infect many different species and TMV: can infect 150 plant species
Narrow host range: very specific in which species/varieties the virus can infect
Bacteriophage phage: virus that infects bacteria

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5
Q

all viruses have
they don’t have

A

capsid: coat protein
genetic material: nucleic acid (dna or rna not both)

cells, cytoplasm, or organelles

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6
Q

+stranded RNA
- stranded RNA
retrovirus

A

acts as mRNA-> protein
template for mRNA -> +RNA -> protein
RNA acts as a template for DNA (RNA -> DNA)

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7
Q

types of single stranded rna

A

+ stranded RNA
- stranded RNA
retrovirus

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8
Q

virus genetic material

A

dsDNA
ssRNA
and some have ssDNA AND dsRNA

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9
Q

many animal viruses have a

A

viral envelope: membrane that surround capsid

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10
Q

viruses reproduce using the ___:

A

machinery
organelles, enzymes, energy

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11
Q

lambda phage

A

infects E. Colu bacteria dsDNA, complex capsid, no membrane

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12
Q

HIV

A

infects human helper T cells ssRNA retrovirus, capsid + envelope

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13
Q

steps in virus reproduction

A

attachment
entry
integration (lysogenic cycle)
synthesis of viral components-lytic
viral assembly-lytic
viral release -lytic

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14
Q

the virus reproductive cycles are

A

lysogenic- viral genome becomes integrated into host chromosome
lytic- virus enters cell and immediately begins to make new virus particles

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15
Q

lysogenic cycle: virus remains ___ in cell while’s its ___ into host cells dna

A

latent = inactive
incorporated

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16
Q

pro virus are in ___ cycle

A

lysogenic

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17
Q

lysogenic cycle: virus goes through a __
viral dna is __
anything made?

A

dormant period
replicated everytime the cells dna is replicated
no new virus particles are made at this time

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18
Q

lytic cycle: virus enters cell and ___
integrated?
lysogenic?

A

immediately makes new virus particles
viral dna may not be integrated into host chromosome
or lysogenic cycle may be very short

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19
Q

lifecycle of lambda phage: 1st step

A

attachment to host cell: protein in tail fibers attaches to proteins on surface of bacterium, in outer bacterial membrane

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20
Q

lifecycle of lambda phage: 2nd step

A

entry: lambda phage injects DNA into cell
capsid never enters the cell but hangs out in the outside

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21
Q

dormant
active

A

lysogenic
lytic

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22
Q

lifecycle of lambda phage: 3rd step

A

integration: phage DNA is integrated into bacterial DNA using enzyme integrase

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23
Q

everytime the ___ cell replicates its dna the __ is also replicated

A

Bacterial
Viral

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24
Q

no new viruses are made during the

A

lysogenic cycle

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25
Q

at the end of the lysogenic cycle viral dna is

A

excised from the bacterial DNA

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26
Q

what controls whether a virus enters lysogenic or lytic cycle

A

environmental factors

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27
Q

lytic cycle: 1st step

A

synthesis of viral components:
new viral protein and DNA are made
viral DNA is circularized
bacterial DNA is degraded

28
Q

lytic cycle: 2nd step

A

assembly of new virus particles:
viral DNA packed inside capsid

29
Q

lytic cycle: 3rd step

A

release:
viral enzyme lysozyme digests bacterial cell wall
bacterial cell lyses= bursts open
new virus particles are released

30
Q

how do you count phage?

A

plaque assay:
plate bacteria in petrified plate to grow a solid layer of bacteria = lawn
some bacteria cells are infected with phage = virus
phage will kill off bacteria and produce clear areas = plaques = circle of death

31
Q

HIV lifecycle: 1st step

A

attachment to host cell:
spike glycogen proteins in viral envelope bind to receptors on pm of helper T cells

32
Q

HIV lifecycle: 2nd step

A

entry:
viral envelope doses with pm of host cell
capsid enter cells
uncaring: cellular enzymes digests coat proteins
viral enzymes and RNA released into cytoplasm

33
Q

HIV lifecycle: 3rd step

A

integration: lysogenic
viral RNA is reverse transcribed to make a dsDNA copy using reverse transcriptase (reverse transcription- RNA make DNA copy)
viral is integrated into host chromosome by enzyme integrase
provirus may be latent for a long period - dormant (not making anything viral so hard to know if you have it)

34
Q

HIV lifestyle: 4th step

A

synthesis of viral components- lytic begins
new viral RNA and proteins are made
spike glycoproteins inserted into pm

35
Q

HIV lifestyle: 5th step

A

viral assembly
new virus particles: capsid protein
2 molecules RNA and 2 molecules reverse transcriptase
capsid assembles with spike glycoproteins during budding

36
Q

2 stage assembly of HIV
capsid proteins assemble around

A

2 molecules HIV RNA
2 molecules reverse transcriptase

37
Q

HIV lifestyle: 6th step

A

release:
Virus buds from host cell
virus gains envelope during budding
cell sheds virus particles without being killed

38
Q

enveloped viruses are released by

A

budding- most envied animal viruses do not kill the host cell as they are released

39
Q

latency - dormant occurs in 2 ways:

A

virus becomes integrated into host DNA (ex HIV)
virus exists as an episome (genetic material element that replicates in cell independently from chromosomes, like plasmid)
sometimes virus can also integrate into chromosome

40
Q

herpes simplex virus type 1:
herpes simplex virus type 2:
varicella zoster:

A

cold sores
genital herpes
chicken pox

41
Q

Latency: varicella zoster
initial:
second:

A

chicken pox- virus may remain latent as episome for years
shingles- when virus shifts from latent to lytic cycle it changes

42
Q

Viruses: H=
N=

A

hemaglutinin- binds to host cell
neuraminidas- helps initiate infection

43
Q

influenza is a ___ virus

A

respiratory

44
Q

Flu vaccine production

A

1) CDC predicts which flu strains will be the most common in the next year
2) injections these flu viruses into eggs to make vaccine (kill virus particles, screen to make sure vaccine works, takes 6 months)
3) construct trivalent or quadivalent (protects against 4 types) flu vaccine and distribute

45
Q

a vaccine __ the immune system and greatly ___. It is not ___

A

primes
greatly decreases the chance of infection
a cure for an existing infection

46
Q

vaccine can eliminate ___ before___

A

virus and virus infected cells
full blown disease develops

47
Q

swine flu:
bird flu:

A

H1N1, 2009
H7N9, 2013

48
Q

which influenza is most worried about

A

H1N1- can cause an epidemic

49
Q

does every animal have a flu virus?

A

yes

50
Q

is it hard for humans to get bird flu?
swine flu?

A

yes
no

51
Q

mixing of proteins from different virus strains occurs in

A

pigs

52
Q

epidemic

A

new flu virus with proteins not normally found in human flu strains made -> no immunity-> epidemic

53
Q

how do viruses become pandemics?

A

reassortment- mixing of genetic material from two strains in one host
it mutates very wuickly

54
Q

emerging viruses

A

viruses or strains of viruses that have arisen recently
more likely to cause disease epidemics
new strands are caused by mutations
viral replicase lacks proofreading
new viruses may be derived from animals and only recently gained the ability to infect humans (change in host range)

55
Q

Origination of new virus

A

reassortment
mutation
change in host range
spread of virus - small isolated population to the rest of the world (air travel)

56
Q

mutation: viral replication is error prone because

new forms of virus may infect individuals who were

A

no proofreading

immune to old virus strain

57
Q

hantavirus:
bird flu:
COVID 19:

A

from rodents, deer mice
from chickens, pigeons
from bats, pangolins

58
Q

most worried form of virus spreading

A

human to human- epidemic
animal -> animal
animal-> human
human-> human

59
Q

SARS

A

severe acute respiratory syndrome
southern china 2002-2003
may have originated in bats
gained ability to infect humans and livestock
type of coronavirus

60
Q

Viruses are grouped into families based on

A

their structure and life cycle

61
Q

some Covid causes
others cause

A

mild infections in humans- common cold
severe infections: sars, mers, covid 19

62
Q

Covid 19 structure

A

genome + stranded rna molecule
capsid: N protein surround the rna
envelope membrane with spike glycoprotein (s) and other proteins (m,h,e)

63
Q

sense strand
antisense strand

A

+ stranded
- stranded

64
Q

what is the first protein to be made from + stranded rna

A

replicase (needed to make more copies of viral RNA)

65
Q

genomic rna

A

the entire rna molecule found in the virus particle
in Covid 19 the genomic rna is a very long mRNA with a 5’ cap and a poly A tail

66
Q

sub genomic

A

shorter mRNAs made form the genomic rna
they are used to make other viral proteins

67
Q

Covid 19 replication process

A

Attachment: uses spike glycoproteins to bind to receptor on cells
entry: viral envelope fuses with pm of cell
uncoating: capsid protein is removed, release +rna into cytoplasm
viral rna is used as mRNA
make replicase enzyme
replicase makes + into -rna

BIO 1200 (17 decks)

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