Intro to Virus

Question 1

Viruses rely on what from host

Answer 1

metabolic machinary of host cells

protein biosynthetic machineray of host cell

Question 2

Intracell phase

Answer 2

replication, transcription, synthesis of proteins and assembly of virons happen inside infected cell

Question 3

What happens in extracell phase

Answer 3

particles must pass from cell to cell or throughout body o between individuals

Question 4

any given virus group is described using a collection of individual properties—not necessarily all properties in common

Answer 4

Polythetic

Question 5

Polytheics key for

Answer 5

idagnosis, idenfificaiton, clarification of life cycle and drug design

Question 6

classificiation depends on

Answer 6

particle type (what it looks like)
tissue trophism( skin vs respiriorty)
diseae etiology
Serology and genome

Question 7

Capsids: made from one or few proteins with repeating _____ contacts—these are self assembling

Answer 7

protein-protein

Question 8

Capsids can form naked viruses or be surrounded by

Answer 8

envelope (matrix proteins lie under envelope)

Question 9

What are packaging, protection and delivery vehicle during transmission

Answer 9

Capside/envelope

Question 10

How do neutralizing antiB targed the virus

Answer 10

Exposed proteins on capsid and membrane are the targets of neurtralizing antiB’s; proteins on outside is the source of epitomes that our immune system targets

Question 11

Whether the virus is naked or enveoloped determines

Answer 11

the virus structure, entry mech and if its suseptible

Question 12

I:

Answer 12

ds DNA to mRNA

Question 13

II:

Answer 13

+ ssDNA to dsDNA to mRNA

Question 14

III:

Answer 14

dsRNA to mRNA

Question 15

IV:

Answer 15

+ssRNA→ -ssRNA→ +mRNA

Question 16

V:

Answer 16

-ssRNA→ + mRNA

Question 17

VI:

Answer 17

+ssRNA → -ssDNA→ dsDNA→ +mRNA

Question 18

RNA viruses capsids are either

Answer 18

Isocahedral or Helical

Question 19

Icosahedral RNA viruses are either

while all helical RNA virusese are

Answer 19

naked or enevloped

enveloped`

Question 20

DNA has three types of capsids:

Answer 20

icosahedral, helical or complex

Question 21

DNA helical and complex viruses are always

Answer 21

enveloped

Question 22

DNA icosahedral viuses can be

Answer 22

Naked or enveloped

Question 23

the viral particle

Answer 23

virion

Question 24

infectious particle

Answer 24

virus

Question 25

multiplicity of infection

Answer 25

MOI

Question 26

cytopathi effect

Answer 26

CPE

Question 27

Plaque assays titration of # of _______, unit = pfu, Take a tissue culture assay for ______infectious virus he plaque or ‘hole’ reflects _______and spread initiated by a single infectious unit (pfu)

Answer 27

infectious progeny quantitiation zone of infection

Question 28

these are intracellular parasites and need to grow INSIDE the cell then you can study what it does to the cell … does it kill it or make it replicate

Answer 28

Cytopathic effect:

Question 29

DNA/RNA + Stuctual proteins +/- EnZ and nucleic acids =

Answer 29

Nucleocapsid (naked capsid virus)

Question 30

Nucleocapsid + glycoproteins and membrane =

Answer 30

enveloped membrane

Question 31

What are components of viral particle

Answer 31

``` genome (nucleoprotein) Enz (few or none) auxillary proteins (dissasmbly) Strucutal proteins (capsid) Attachment and fusion proteins ```

Question 32

During replication... the regulatory phase is ____ while the structual phase is _____

Answer 32

early | late

Question 33

Goal of infectious virus

Answer 33

hold host at bay long enought to undergo replication rlease at the level of cell's anitival response and the immune system

Question 34

6 steps to viral life cycle

Answer 34

1. Attachment 2. Penetration 3. Uncoating: 4. Synthesis of components:s 5. Assembly of viral components 6. exit and maturation

Question 35

Virion Attachment Both naked and enveloped:

Answer 35

viral surface protein recognized a receptor on the target cell

Question 36

What happens during uncoating

Answer 36

synthesis of viral mRNA translation of viral proteins genome replication

Question 37

Both naked and enveloped: viral surface protein recognized a ____ on the target cell

Answer 37

receptor

Question 38

Cell surface receptors (proteins or carbs) often determine | AntiBs that interfere with this intercation can ‘neutralize’ viral infectivity

Answer 38

species or tissue tropism

Question 39

Receptors may be ubiquitious or cell type specific | Virus recognition of its receptors is important for determing:

Answer 39

host range, (humans vs others) and cell tropism (which cell type it will infect)

Question 40

Virion Entry: | 1. Naked; enter cell via _______ and are surrounded by endosomal membrane (will get taken up into a vesicle)

Answer 40

Endocytosis

Question 41

Virion entry Enveloped: use their ______to induce fusion of virus and cell→ fusion will release ______into cytoplasm, leaving traces of viral protein in the membrane

Answer 41

glycoprotein | capsid

Question 42

other enveloped taken up via endocytosis and fusion of their membrane with

Answer 42

membrane of acidic endosomal compartment→ will then release capsid into cytoplasm

Question 43

Cells do not have enZs that copy RNA→ | or RNA→

Answer 43

RNA | DNA

Question 44

ALL viruses must synthesis _____ to make proteins

Answer 44

+mRNA

Question 45

ALL viruses use ______ to make viral proteins but viral proteins can modify their translational specificity

Answer 45

host ribs

Question 46

Viruses can use _____OR _____machinary to modify proteins

Answer 46

host | viral

Question 47

many viruses______ host macromolecular synthesis; other manipulate cell cycle of host to get the best replicative environment

Answer 47

‘shut off’

Question 48

proteins are sorted to correct nuclear or cytoplasmic location capsid proteins must_______ viral genome must be selectively ________

Answer 48

assemble | encapsidated

Question 49

Viral membrane proteins must be synthesized, modified and trafficked to correct membrane; - translation (in the ____) - Glycosylation (in ____) - transport to membrane (______) by vesicular transport

Answer 49

ER golgi internal or lasma

Question 50

viruses can aquire a membrane in

Answer 50

cytoplasm

Question 51

viruses can buc:

Answer 51

from nucleuar envelpoe into compartments of secreatory path from plasma membrane

Question 52

once viral proteins replicated, virus replicates its________ and assembles into:

Answer 52

genome | progeny virion

Question 53

Naked cells rely on ____ for rlease

Answer 53

cell lysis

Question 54

Enveloped viruses are released by

Answer 54

budding

Question 55

Capsid assemble and release in

Answer 55

coupled process at the plasma membrane | --capsid has lipid env from cell and has own viral proteins

Question 56

leads to cytophathi effect with burst of virus produciton

Answer 56

productive infection

Question 57

on production of infectious particles but genetic information of virust remains

Answer 57

latent infection

Question 58

chronin virus production

Answer 58

persistant infection

Question 59

viurs lifecycle incomplete and virus lost

Answer 59

abortive infection

Question 60

Acute cytopathic effects of virus on host

Answer 60

mmb fusion of adj cells→ get giant multi-nucleated syncytia shut off host metabolism induction of apoptosis Cell death—necorsis

Question 61

Cell transormation from virus

Answer 61

loss of normal growth = oncogenic potential

Question 62

Tropism of virus determined by

Answer 62

recepors, tissues specific components, tissue specific restrictions to abort infection, temp or pH

Question 63

Viruses will cause pathogeneisis by:

Answer 63

destruction of infected cell modify infected cell function immune and immlamator response

Question 64

Innate response ____________ interfeurons, cytokines, chemokines, antiviral response in infected cell -makes surrounding cells resistant to infection -recruits effect cells (NK cell or macrophages) -or apoptosis

Answer 64

Soluble mediators

Question 65

Adaptive immune response humoral

Answer 65

neutralizing antiB: block entry/attachment | complement fixing: lyse virions or infected cell

Question 66

Adaptive response: cell mediated

Answer 66

MHC presentation-- Cytotoxic T cell

Question 67

Memory response

Answer 67

B and T cell to reisit infection