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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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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
at the end of the lysogenic cycle viral dna is
excised from the bacterial DNA
26
what controls whether a virus enters lysogenic or lytic cycle
environmental factors
27
lytic cycle: 1st step
synthesis of viral components: new viral protein and DNA are made viral DNA is circularized bacterial DNA is degraded
28
lytic cycle: 2nd step
assembly of new virus particles: viral DNA packed inside capsid
29
lytic cycle: 3rd step
release: viral enzyme lysozyme digests bacterial cell wall bacterial cell lyses= bursts open new virus particles are released
30
how do you count phage?
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
HIV lifecycle: 1st step
attachment to host cell: spike glycogen proteins in viral envelope bind to receptors on pm of helper T cells
32
HIV lifecycle: 2nd step
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
HIV lifecycle: 3rd step
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
HIV lifestyle: 4th step
synthesis of viral components- lytic begins new viral RNA and proteins are made spike glycoproteins inserted into pm
35
HIV lifestyle: 5th step
viral assembly new virus particles: capsid protein 2 molecules RNA and 2 molecules reverse transcriptase capsid assembles with spike glycoproteins during budding
36
2 stage assembly of HIV capsid proteins assemble around
2 molecules HIV RNA 2 molecules reverse transcriptase
37
HIV lifestyle: 6th step
release: Virus buds from host cell virus gains envelope during budding cell sheds virus particles without being killed
38
enveloped viruses are released by
budding- most envied animal viruses do not kill the host cell as they are released
39
latency - dormant occurs in 2 ways:
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
herpes simplex virus type 1: herpes simplex virus type 2: varicella zoster:
cold sores genital herpes chicken pox
41
Latency: varicella zoster initial: second:
chicken pox- virus may remain latent as episome for years shingles- when virus shifts from latent to lytic cycle it changes
42
Viruses: H= N=
hemaglutinin- binds to host cell neuraminidas- helps initiate infection
43
influenza is a ___ virus
respiratory
44
Flu vaccine production
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
a vaccine __ the immune system and greatly ___. It is not ___
primes greatly decreases the chance of infection a cure for an existing infection
46
vaccine can eliminate ___ before___
virus and virus infected cells full blown disease develops
47
swine flu: bird flu:
H1N1, 2009 H7N9, 2013
48
which influenza is most worried about
H1N1- can cause an epidemic
49
does every animal have a flu virus?
yes
50
is it hard for humans to get bird flu? swine flu?
yes no
51
mixing of proteins from different virus strains occurs in
pigs
52
epidemic
new flu virus with proteins not normally found in human flu strains made -> no immunity-> epidemic
53
how do viruses become pandemics?
reassortment- mixing of genetic material from two strains in one host it mutates very wuickly
54
emerging viruses
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
Origination of new virus
reassortment mutation change in host range spread of virus - small isolated population to the rest of the world (air travel)
56
mutation: viral replication is error prone because new forms of virus may infect individuals who were
no proofreading immune to old virus strain
57
hantavirus: bird flu: COVID 19:
from rodents, deer mice from chickens, pigeons from bats, pangolins
58
most worried form of virus spreading
human to human- epidemic animal -> animal animal-> human human-> human
59
SARS
severe acute respiratory syndrome southern china 2002-2003 may have originated in bats gained ability to infect humans and livestock type of coronavirus
60
Viruses are grouped into families based on
their structure and life cycle
61
some Covid causes others cause
mild infections in humans- common cold severe infections: sars, mers, covid 19
62
Covid 19 structure
genome + stranded rna molecule capsid: N protein surround the rna envelope membrane with spike glycoprotein (s) and other proteins (m,h,e)
63
sense strand antisense strand
+ stranded - stranded
64
what is the first protein to be made from + stranded rna
replicase (needed to make more copies of viral RNA)
65
genomic rna
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
sub genomic
shorter mRNAs made form the genomic rna they are used to make other viral proteins
67
Covid 19 replication process
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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