Mcb Exam 4 Uf Cop Part 1

Front 1

w/c type of microscope is needed to view viruses?

Back 1

electron

Front 2

what is the size of viruses?

Back 2

most are <0.45microns

Front 3

_______ is the inactive form of the virus?

Back 3

virion

Front 4

when does a virion become a virus?

Back 4

once inside in the host, it becomes a virus & active

Front 5

what are the different nucleic acids of viruses?

Back 5

DNA or RNA w/c can be SS or DS

Front 6

what is the function of a capsid on viruses?

Back 6

to protect DNA/RNA against physcal or chemical damage

Front 7

what is the shape of all viruses?

Back 7

icosohedron & some are helical

Front 8

this viral structure is involved in recognizing the host surface?

Back 8

capsid

Front 9

what are the 3 functions of capsid?

Back 9

protects DNA/RNA against physical chemical damage, involved in recognizing the host surface, & facilitates nucleic acid penetration

Front 10

viral envelops are composed of what?

Back 10

host lipids & viral proteins

Front 11

function of viral spikes?

Back 11

used for recognition & attachment to host

Front 12

what are the 4 structures a virus can have?

Back 12

nucleic acid, capsid, envelope, & spike

Front 13

w/c structures are required for a virus to have?

Back 13

nucleic acid & capsid

Front 14

When growing viruses, what is required?

Back 14

A host

Front 15

What is a plaque assay?

Back 15

Host + virus

Front 16

What are the tissue culture technique?

Back 16

in the dish, u see the spots. These are where the virus has attacked the host tissue w/c the opaque part on the dish.

Front 17

The affinity of the virus to its host is known as?

Back 17

tropism

Front 18

this term defines taking the virus & passing it thru the host to produce more viruses?

Back 18

passing

Front 19

What are the 4 types of infections involved in human viruses?

Back 19

Lytic, persistent, transforming, & latent

Front 20

This infection involves the death of the host & release of virus?

Back 20

Lytic

Front 21

Define transforming infection?

Back 21

When virus inserts itself w/n the host chromosome & therefore replicates along w/ the chromosome. This could lead to mutation or transformation w/c is a change in the genetic make up of the cell.

Front 22

Give an example of a latent infection?

Back 22

Herpes

Front 23

2 types of infections that affect the bacteria by viruses?

Back 23

Lytic & lysogenic

Front 24

What are the non specific responses of host to virus?

Back 24

Fever, interferon, low pH of inflammatory exudates, mucous, hyrolytic enzymes

Front 25

These are major defenses agains viruses & they are the 1st line of defense?

Back 25

Interferons

Front 26

What are interferons?

Back 26

Cytokines that are released by WBC & are a major defense against viruses

Front 27

How does low pH work in inhbiting viral infection?

Back 27

some viruses go inside w/ their capsid intact. To uncoat (for the capsid to come off) it requires a certain pH so if u lower the pH, the virus will be able to unooat & therefore cannot release the virus.

Front 28

How do hyrolytic enzymes work in viral infection?

Back 28

They destroy viral components. Examples are proteases & nucleases

Front 29

What are the specific defenses of viral infection?

Back 29

Ab & CMI

Front 30

What is the virulence factors of viruses?

Back 30

To be able to enter the cell & reprogram the host so the host produces more viruses

Front 31

What are the 2 ways that the host tries to get rid of the virus?

Back 31

Cytopathology & immunopathology

Front 32

A host defense where the cell is lysed so it can get rid of the virus by getting rid of the machinery of the cell?

Back 32

Cytopathology

Front 33

A host defense where the immune system tries to minimize the damage & tries to get rid of the pool of cells that have the virus w/n them so it gets rid of their own cells?

Back 33

immunopathology

Front 34

2 ways a virus can enter into host tissue?

Back 34

Directly by trauma or insect bite & thru mucous membranes of the respiratory & alimentary tracts

Front 35

What is the MC way that a virus can get into the host?

Back 35

respiratory

Front 36

These are effects that are visual w/c can be seen under microscope or observe the outcome of a viral infection?

Back 36

Cytopathic effects (CPE)

Front 37

What are the 4 ways that a virus can damage the host?

Back 37

1) cell lysis 2) cell transformation where the DNA is altered, 3) toxic products 4) alter host structure

Front 38

virus enters the blood stream is a condition ka?

Back 38

viremia

Front 39

what are the 8 mechanisms of the virus replication cycle?

Back 39

attachment, penetration, uncoating, provision of energy, synthesis of precursors, nucleic acid & protein synthesis, assembly, & release

Front 40

attachment of virus to host occurs by what way?

Back 40

specific; most of the time occurs between the capsid & the host receptors & may also occur between the spkes & the host receptors

Front 41

what is the function of the synthesis of precursors in virus replication cycle?

Back 41

earlier proteins are made w/c are enzymes that are needed for replication

Front 42

what is maturation in virus replication cycle?

Back 42

virus is produced in pieces first then assembled later

Front 43

T/F: release or exit of virus in its replication cycle always involves killing the host?

Back 43

False, not always

Front 44

what 3 things can lead to cell lysis & therefore host damage w/ viral infection?

Back 44

Ab-virus-host cell, complement-Ab-virus-host cell, & expression of viral protein on host surface. These will all lead to lysis of the cell.

Front 45

what is the main weapon of the host in viral infection?

Back 45

CMI

Front 46

these cells are important in killing intracellular pathogens or infected cells?

Back 46

natural killer cells

Front 47

what are the 7 ways that viruses can evade the immune response of the host?

Back 47

1) inhibition of MHC class I, 2) inhibition of MHC II, 3) downregulation of CD4 by HIV, 4) inhibition of NK cell lysis, 5) interference w/ apoptosis, 6) inhibition of cytokine action (interferons), 7) evasion of humoral immunity

Front 48

how can a virus evade the humoral immunity of the host?

Back 48

evade by mutation, antigenic shift or drift

Front 49

for viral infection, the site of infection is the _______ ________ of infection?

Back 49

primary site

Front 50

what is the MC way of viral infection spread in the body?

Back 50

subepithelial invasion & lymphatic spread

Front 51

secondary viremia can happen by what 3 ways?

Back 51

virus enters the lymph system, virus enters the blood stream, or virus enters the NS. This is how the virus spreads thru the rest of the body

Front 52

virus entering the lymph system is ka?

Back 52

lymphotropic

Front 53

virus entering the NS is ka?

Back 53

neurotropic

Front 54

what are the different ways that viruses can shed?

Back 54

respiratory or oropharyngeal secretions, feces, skin, urine, milk, genital secretions, blood

Front 55

T/F: all viruses shed to be able to infect others organisms?

Back 55

False, not all viruses are involved in virus shedding.

Front 56

all of the visual damages to the host by the virus is ka?

Back 56

cytopathic effects or CPE

Front 57

T/F: usually viruses don't want to kill their host so lysis is not the preferred method for a virus?

Back 57

True

Front 58

what are permissive or productive virus cell interaction infections?

Back 58

Permissive or productive infection: go in, make viruses & then get out

Front 59

what are the types of virus cell interactions in viral infections?

Back 59

permissive or productive, abortive or non productive, persisten, latent, & CPE

Front 60

what is the normal outcome for virus cell interactions for a viral infection?

Back 60

permissive or productive infection

Front 61

define abortive or non productive infection in viral infection?

Back 61

virus enters the cell then a few genes are turned on but no further expression occurs

Front 62

when does lysogeny of the virus become lytic?

Back 62

under some kind of stress, it will become lytic & start doing damage

Front 63

what happens in persistent viral infection?

Back 63

there are a few cells that produce the virus after the permissive cells die & release the virus. At this point, interferon inhibits the infection but Ab do not clear it from the body

Front 64

what happens in latent viral infection?

Back 64

Some viruses, instead of reproducing, enter into a latent state from which they can later be reactivated

Front 65

give 2 examples of latent infection & how they work?

Back 65

herpes where DNA is methlyated but is not integrated w/n the host chromosome. Adeno-associated where it integrates into the host genome & therefore can replicate when host genome replicates.

Front 66

Give some examples of CPE?

Back 66

1)Changes in structure of nucleus, 2)Changes in membrane, fibroblast and viral budding & 3)Cell fusion

Front 67

in viral infection, cell fusion is aka?

Back 67

syncytia formation

Front 68

what makes up the one step growth cycle?

Back 68

attach or adsorb to cell, penetration of virus, eclipse, & rise

Front 69

penetration of virus into host can occur by what 2 ways?

Back 69

fusion or endocytosis

Front 70

what happens in the eclipse part of the one step growth cycle?

Back 70

infecitous virus is not detectable

Front 71

what happens in the rise stage of the one step growth cycle?

Back 71

infectious particles are detectable

Front 72

what are the viral replication steps?

Back 72

Front 73

what is a clatherin coated pit?

Back 73

once a virus enters by endocytosis, it becomes surrounded by this coated vesicle

Front 74

clartherin coated pits require what?

Back 74

low pH in the cytoplasm for the virus to release its particles

Front 75

Define viral syndrome. Give some examples of viral syndromes

Back 75

a. Viral Syndrome: the pathogenic manifestation of a viral infection.
b. Examples include: oral and respiratory tract infections, infections of the eye, hepatitis, and etc.

Front 76

A process by which cells internalize molecules (endocytosis) by the inward budding of plasma membrane vesicles containing proteins with receptor sites specific to the molecules being internalized.

Back 76

receptor mediated endocytosis

Front 77

how does a virus replicate in the host?

Back 77

it uses host cell enzymes & structural components such as actin fibers, membranes & ribosomes

Front 78

what enzymes can be used by the virus to undergo transcription?

Back 78

cellular transcriptase & viral transcriptase

Front 79

T/F: viruses use only the host cellular enzymes to undergo transcription?

Back 79

false, some viruses have their own viral transcriptase enzymes to help them undergo transcription

Front 80

Influenza virus is what type of virus?
a) RNA virus
b) DNA virus

Back 80

A) RNA virus

Front 81

Be familiar w/ infections associated w/ viral syndromes

Back 81

Front 82

w/c viruses can trigger fusion of neighboring cells called syncytia?

Back 82

paramyxoviruses, herpesviruses, & retroviruses

Front 83

What the important features of AZT?

Back 83

Azine group instead of hydroxyl – acts as a chain terminator

Front 84

Why is it so difficult to develop vaccine for HIV

Back 84

HIV has a high mutation rate
The disease is spread by so many different transmission routes,
vaccine against the mucosal lining is difficult, and so many subtypes
exist

Front 85

What is the possible origin of HIV? What are the clads, groups and subtypes of HIV

Back 85

a. Simian (SIV). Origin is from the simian lentiviruses. More specifically, HIV-1 from
SIV- CPZ and HIV-2 from SIV-SM.
Groups > Subtypes > Clads

Front 86

In HIV, what is the MC transmission? what is the most effective transmission?

Back 86

The most common is sexual, but the most EFFECTIVE is blood transfusion.