Viral Replication (Attachment and Entry) Flashcards
1
Q
___ must first gain proximity to a cell within a
susceptible organism
A
virus
2
Q
are infectious diseases that can be transmitted from animals to humans
A
zoonotic viruses
3
Q
Free- living bacterial cells encounter virus in the
environment through
A
random diffusion
4
Q
encounter virus in the
environment through random diffusion.
A
free living bacterial cells
5
Q
For plants, viruses commonly delivered to a new host by
a
A
vector species
6
Q
For ___, viruses commonly delivered to a new host by
a vector species
A
plants
7
Q
In ___, viruses may be delivered to the body surface
by a vector or by direct contact with particles on
surfaces,
A
animasl
8
Q
In animals, viruses may be delivered to the body surface
A
vector
direct contant with particles
9
Q
or else viruses can be internalized into the body from the
environment via what tracts (3)
A
respiratory
GI
genital
10
Q
need to have preferred mode of entry if they are to multiply
A
viruses
11
Q
(prefer
to enter the respiratory system and multiply; if not, they will likely
not cause any disease)
A
respiratory viruses
12
Q
mothers can also transfer HIV to your child thru its ___ and __
A
placenta
blood
13
Q
___ (part of a virion) must enter a cell for the viral reproduction cycle to occur.
A
genome
14
Q
Physical properties of the virion are obstacles to this – viruses too large to diffuse passively across the __ ___
A
plasma menbrane
15
Q
cell drinking
A
pinocytosis
16
Q
is an active, energy consuming process where extracellular fluid and solutes are taken up into a cell via small vesicles.
A
pinocytosis
17
Q
cell eating
A
phagocytosis
18
Q
is the process by which a cell takes in large particles, such as microorganisms or dead cell
A
phagocytosis
19
Q
First step is adherence of virus particles to the plasma membrane specific ___ molecule on the cell
surface
A
receptor
20
Q
plays an important role in uncoating
A
adhering of virion to the plasma membrane specific receptor molecule on cell surface
21
Q
is the process where a virus, after entering a host cell, disassembles its protective capsid (or envelope) shell to release the viral genome, allowing for replication and transcription.
A
uncoating
22
Q
site of replication of RNA-containing viruses
A
cytoplasm
23
Q
site of replication of DNA-containing viruses and RNA-containing retroviruses,
A
nucleus
24
Q
can freely exist in the cytoplasm but its replication can be a different
thing
A
+ssRNA
25
Uses normal cellular processes, including endocytosis, membrane fusion, vesicular trafficking, and transport
into the nucleus.
viral replication
26
overview of virus replication (7)
Attachment
Entry
Transcription
Translation
Genome replication
Assembly
Exit
27
all animal viruses must cross the ___ ___
plasma membrane
28
some animal viruses are transported in the cytoplasm via
microtubules
29
animal viruses must also cross the nuclear envelope via
nuclear pore
30
The aim of a virus is to __ and in order to
achieve this aim it needs to enter a host cell, make
copies of itself and get the new copies out of the cell.
replicate
31
The aim of a virus is to replicate and in order to
achieve this aim it needs to enter a host cell, make
copies of ____ and get the new copies out of the cell.
itself
32
process of various replication can be broken down into seven steps:
Attachment of virion to the cell
Enter into the cell
Transcription of virus genes into messenger RNA molecules (mRNAs)
Translation of virus mRNAs into virus proteins
Genome replication
Assembly of proteins and genomes into virions
exit of the virions from the cell.
33
step 1 of virus replication
attachment of virion to a cell
34
attachment: tail fibers attach to cell wall proteins
bacteriophage or animal virus?
bacteriophage
35
attachment: attachment sites are plasma membrane proteins
bacteriophage or animal virus?
animal virus
36
entry: capsid enters by receptor-mediated endocytosis
bacteriophage or animal virus?
animal virus
37
entry: viral DNA is injected into host cell
bacteriophage or animal virus?
bacteriophage
38
bacteriophage or animal virus?
uncoating: enzymatic removal of capsid proteins
animal virus
39
bacteriophage or animal virus?
uncoating not required
bacteriophage
40
bacteriophage or animal virus?
biosynthesis in cytoplasm
bacteriophage
41
bacteriophage or animal virus?
biosynthesis in nucleus (DNA viruses) or cytoplasm (RNA viruses)
animal virus
42
chronic infection: lysogeny
bacteriophage or animal virus?
bacteriophage
43
chronic infection: latency; slow viral infections; cancer
bacteriophage or animal virus?
animal viruses
44
bacteriophage or animal virus?
released: host cell is lysed
bacteriophage
45
bacteriophage or animal virus?
release: enveloped viruses buds out; non-enveloped viruses rupture plasma membrane
animal viruses
46
is a viral reproduction cycle where a bacteriophage (phage) integrates its DNA into a host bacterium's genome
lysogeny
47
bacteria can be resistant to all ___ but do not have a response to bacteriophages
antibiotics
48
stage of viral replication where virion attaches to cell
attachment
49
stage of viral replication where virion enters the cell and its DNA is uncoated
Entry and Uncoating
50
stage of viral replication where a portion of viral DNA is transcribed, producing mRNA that encodes early viral protein
transcription
51
stage of viral replication where viral DNA is replicated, and some viral proteins are made
biosynthesis
52
stage of viral replication where capsid proteins are synthesized
late translation
53
stage of viral replication where virions mature
maturation
54
stage of viral replication where virions are released
release
55
* distributed over the surface of the animal virus.
attachment proteins
56
Binding of the attachment proteins to target cell receptors brings the ___
___of the virus envelope and the host membrane into close
proximity.
lipid bilayer
57
* sites vary from one group of viruses to another.
attachment proteins
58
In ____, which are icosahedral viruses, the attachment sites are
small fibers at the corners of the icosahedron
adenoviruses
59
In adenoviruses, which are ___viruses, the attachment sites are
small fibers at the corners of the icosahedron (
icosahedral
60
In adenoviruses, which are icosahedral viruses, the attachment sites are
___fibers at the corners of the icosahedron (
small
61
In ___viruses, such as influenza virus, the attachment sites are
spikes on the surface of the envelope.
enveloped
62
In ___viruses, such as influenza virus, the attachment sites are
spikes on the surface of the envelope.
enveloped
63
In enveloped viruses, such as influenza virus, the attachment sites are
spikes on the surface of the ___.
enveloped
64
As soon as one spike attaches to a host receptor, additional receptor sites
on the same cell __to the virus.
migrate
65
* ___is completed when many sites are bound.
attachment
66
HIV will not attach to other cells than
CD4+
67
Infection of cells by many, but not all, viruses requires
binding to a ___on the cell surface.
receptor
68
is a cell surface molecule that binds the virus
particle (attachment proteins) and participates in entry.
receptor
69
receptors are ___characteristics of the host
inherited
70
receptors of the genetic disease
can be found in the ___(e.g.
breast cancer)
offsprings
71
receptors are made up of
proteins
carbohydrates
lipids
72
purpose of receptors in the body
acting as receptors for chemokines and growth factors;
mediating cell-to-cell contact and adhesion
73
receptors in the body acts as receptors for ___and ___ ___;
chemokines
growth factors
74
receptors in the body function in mediating ____ and ___
cell to cell contact
adhesion
75
purpose of receptor for virus replication
induce conformational changes in the virus particle that lead to
membrane fusion or penetration,
* it may also transmit signals that cause uptake
* bring the bound particle into endocytic pathways.
76
receptors in the body induce ___ changes in the virus particle that lead to
membrane fusion or penetration,
conformatonal
77
receptors in the body induce conformational changes in the virus particle that lead to
___ or ___
membrane fusion
penetration
78
receptors in the body transmit signals that cause ___
uptake
79
receptors in the body bring the bound particle into ___pathways.
endocytic
80
is a cellular process that involves the internalization of extracellular materials or membrane proteins by invagination of the cell membrane, forming vesicles inside the cell, which then sort and transport these materials for various functions.
endocytic pathway
81
* Receptors plus ___ for other viruses
co-receptors
82
Different receptors may serve for virus entry in
___ cell types, and unrelated viruses may bind to
the same receptor
diverse
83
Different receptors may serve for virus entry in
diverse cell types, and unrelated viruses may bind to
the ___receptor
same
84
determine the host range of a virus, i.e., its ability to
infect a particular animal or cell culture.
cell receptor
85
infects primates and primate cell cultures
but not mice or mouse cell cultures.
poliovirus
86
Receptors can also be determinants of
tissue tropism
87
the predilection of a virus to invade and
reproduce in a particular cell type.
tissue tropism
88
have receptors for hepatitis virus (not immune cells) due to different
gene expression in somatic cells
hepatocytes
89
receptors can be made up of
carbohydrate
lipid
90
After binding to receptors animal viruses must cross the
__ ___ to gain entry to the host cell
plasma membrane
91
two ways to enter the plasma membrane
endocytosis
fusion of viral envelop with host cell membrane
92
creates an endosome; rides with clathrin
mediated, and caveolin-mediated endocytosis
endocytosis
93
proteins that force the membrane to bend around a
particle
clathrin
caveoline
94
Endosome then fuses with ___
lysosome
95
Many viruses (naked) enter
into eukaryotic cells by
receptor-mediated endocytosis
96
brings the food into lysosome where the contents of the
endosome are ultimately digested and broken down
endosome
97
If a virion attaches to the
plasma membrane of a
potential host cell, the host
cell will enfold the virion
into a fold of plasma
membrane, forming a
vesicle
98
human species C adenoviruses that utilize ___as their receptor
CAR
99
Attachment facilitates a secondary interaction between
capsid protein (penton base)
cell surface integrins
100
the capsid protein at
the base of the fiber, known as ___base, and cell surface integrins
penton
101
These are proteins found on the surface of cells that help cells adhere to each other and to the extracellular matrix. They also play a role in signaling pathways that regulate cell behavior.
integrins
102
Enveloped viruses can enter
by a method called
fusion
103
in which the viral envelope
fuses with the plasma
membrane and releases the
capsid into the cell’s
cytoplasm.
fusion
104
type of entry that will only retain the capsid
fusion
105
Another Entry by enveloped
virus is thru endocytosis
followed by a ___ of the
envelope with the
endosome
fusion
106
endosome has an ___ pH
acidic
107
promotes
conformational changes in
viral proteins and the fusion
of the membranes.
pH
108
Once in the cell the virus, or at least its genome, may have to be delivered to a particular
location, such as the __.
nucleusd
109
destination of the genome can be reached thru
microtubules
110
which convert their genome to DNA in the cytoplasm
retroviruses
111
The nucleocapsid is
transported from the plus end
of a microtubule near the
plasma membrane to the
___, which is located
close to the nucleus
centrosome
112
are large, complex, and
non- enveloped, with a characteristic head
and-tail structure
t-even bacteriophages
113
__has enough DNA for over 100 genes.
phage
114
phage has enough ___for over 100 genes.
DNA
115
five distinct stage of a lytic cycle of t-even bacteriophage
attachment
penetration
biosynthesis
maturation
release
116
Bacteriophages can multiply by two alternative
mechanisms:
lytic cycle
lysogenic cycle
117
ends with the lysis and death of the
host cell,
lytic cycle
118
whereas the host cell remains alive in
the
lysogenic cycle
119
receptors in bacterial cells
* iron-uptake protein
carbohydrate in lipopolysaccharide
receptor for phage lambda
120
a tailed phage of
Escherichia coli, is maltoporin,
which is a high affinity
maltose binding/transporter
protein
lambda phage
121
Phages used the distal ends of the long
___ to connect to host receptors
tail fibers
122
Complete contact made between the
short pins extending from the base
plate and the cell wall;
what attachment
bacteriophages
123
phage’s tail releases an enzyme, ___, which
breaks down a portion of the bacterial cell wall.
phage lysozyme
124
tail sheath of the phage contracts, and the ____ ___ is
driven through the cell wall.
tail core
125
enzyme of bacteriophage that breaks down a portion of the bacterial cell wall.
lysozyme
126
tail sheath of the phage ___, and the tail core is
driven through the cell wall.
contract
127
shortening of the __ ___pushes the non-contractile
tail core through the outer layers of the bacterium with
a twisting motion
tail sheath
128
shortening of the tail sheath pushes the non-contractile
tail core through the outer layers of the bacterium with
a __ ___
twisting motion
129
When the tip of the core reaches the plasma membrane,
the ___from the bacteriophage’s head passes through
the tail core through the plasma membrane, and enters
the bacterial cell.
DNA
130
When the tip of the core reaches the plasma membrane,
the DNA from the bacteriophage’s head passes through
the tail core, through the _____ , and enters
the bacterial cell.
plasma membrane
131
T-even bacteriophage injects its ___ (nucleic acid) into
the bacterium.
DNA
132
injects its DNA (nucleic acid) into
the bacterium.
t-even bacteriophage
133
contraction of the ___ forces the injection
of the phage DNA through the tail core
into the cell
head
134
remains outside the bacterial cell. in bacteriophage entry
capsid
135
Therefore, the ___particle functions like
a hypodermic syringe to inject its DNA into
the bacterial cell.
phage
136
