Micro2. Chaps 14

Front 1

Animal viruses have an _____ or _____ genome that is either double or single stranded.

Back 1

DNA or RNA

Front 2

Animal viruses are surrounded by a protein coat called a _______.

Back 2

Capsid

Front 3

The nucleic acid and the capsid are called __________.

Back 3

Nucleocapsid

Front 4

Some viruses have an ________ which acts as a phospholipid bilayer membrane that was obtained from the cell in which the virus arose.

Back 4

Envelope

Front 5

Viruses are _________ intracellular ___________.

Back 5

Obligate intracellular parasites.

Front 6

Viral genomes vary. Define:
Polioviruses
Herpeviruses
Retroviruses
Influenza viruses

Back 6

Poliovirus = ss RNA
Herpevirus = ds DNA
Retrovirus = Diploid ss RNA
Influenza Virus = multiple gene segments of ss RNA

Front 7

What is the simplist genome and largest genomes of animal viruses?

Back 7

Hantavirus = simplist = 3 genes that encode 4 polypeptides
Pox virus = most complicated = 200 genes

Front 8

What is the nomenclature rule for viruses?

Back 8

Viruses are names for the geographic region in which they are discovered.

Front 9

What are the three things that are used to classify viruses?

Back 9

1. Genome structure
2. Virus particle structure
3. Presence or absence of an envelope

Front 10

Viruses are grouped based on their __________ _________.

Back 10

Transmission mechanism

Front 11

What are the four groupings of transmission mechanisms?

Back 11

1. Enteric viruses (fecal-oral route)
2. Respiratory viruses (aerosols)
3. Zoonotic agents (biting or resp. route)
4. Sexually-tranmitted

Front 12

Viruses tend to be species and cell ________.

Back 12

Specific

Front 13

Step 1 of infection is called __________.

Back 13

Attachement

Front 14

Attachement is mediated by ____-_______ molecule(s) and viral ______ _______.

Back 14

Cell-surface
spike proteins

Front 15

HIV gp120 is specific for CD4, which are principally found on ________ ____ cells.

Back 15

Helper T cells

Front 16

Attachement occurs by _________ interactions.

Back 16

Noncovalent

Front 17

Some viruses ______ with a cell's plasma membrane. HIV's gp___ interacts with a cellular __________ receptor to induce fusion.

Back 17

Fuse
gp41
chemokine

Front 18

In both fusion and endocytosis, the ________, containing the nucleic acid and viral enzymes, is ________ into the _________.

Back 18

Capsid
dumped
cytoplasm

Front 19

Most DNA viruses replicate in the __________, while most RNA viruses replicate in the __________.

Back 19

DNA = Nucleus
RNA = Cytoplasm

Front 20

Some viruses ________ their dsDNA into the host cell's genome. Some viruses copy their RNA into ______, which is then integrated into the host cell's genome.

Back 20

Integrate
dsDNA

Front 21

Uncoating is caused by the dissociation of the _______ _______ from the ________ subunits that make up the capsid. This causes the capsid to ___________ and liberates the nucleic acid.

Back 21

Nucleic Acids
Protein subunits
Disintegrate

Front 22

Some RNA virus genomes act as a mRNA, these are termed:

Back 22

plus-strand viruses

Front 23

If a virus is not a plus-strand it has a prepackaged, _____-encoded ____-dependant RNA pol and is termed a ______-strand virus.

Back 23

virus-encoded
RNA-dependant
Minus-strand

Front 24

DNA viruses encode ____ polymerases.

Back 24

RNA

Front 25

Many viruses have ______cistronic mRNA's.

Back 25

Polycistronic

Front 26

Step 6 of infection is:

Back 26

Maturation

Front 27

Maturation of a virus in a cell involves the ________ of polycistronic polypeptides into ________.

Back 27

Cleavage
Subunits

Front 28

Nucleic acids and capsid proteins spontaneously __________ into ___________.

Back 28

Polymerize
Nucleocapsid

Front 29

HIV gp____ polypeoptide is cleaved into its gp____ and gp___ mature polypeptides. This step is inhibited by the ____ ________ __________ taken by HIV+ people.

Back 29

gp160 --> gp120 and gp41
HIV protease inhibitors

Front 30

Step 7 of infection is:

Back 30

Release from cells

Front 31

Some viruses rely upon _____ ______ for release into the extracellular matrix. This is like a balloon being blown up till it pops.

Back 31

Cell lysis

Front 32

Other viruses rely upon ________, whereby they exit from the cell, taking some of its membrane. These viruses don't exceed the capacity of the cell.

Back 32

Budding

Front 33

Budding occurs in one of three places depending on the viral species, these locations are:

Back 33

The plasma membrane, the Golgi or the ER

Front 34

Step 8 of viral infection is:

Back 34

Shedding from the host

Front 35

__________ ________ ________ would be an example of a catastrophic shedding event, while a ______ _____ is an example of a minor shedding event.

Back 35

Hemorrhagic fever virus
Common cold virus

Front 36

Step 9 of infection is:

Back 36

Trasmission to other hosts

Front 37

Transmission routes usually reflect the ______ of _________ for viruses.

Back 37

Site of infection

Front 38

List the 3 types of persistant infections:

Back 38

1. Latent
2. Chronic
3. Slow

Front 39

Hepatitis ___ is the greatest current health risk.

Back 39

C

Front 40

__________ ________ refers to even if you get vaccinated, if you're exposed heavily, you can still get the virus.

Back 40

Vaccine breakthru

Front 41

List the 3 mechanisms that account for viruses driving cell proliferation:

Back 41

1. Oncogenes stimulate cell proliferation
2. Viral DNA integrates adjacent to genes that drive cell division
3. Some viruses encode growth factors

Front 42

Epstein-Barr virus encodes the growth factor _______ __________-10 that causes ___ cell proliferation, leading to ________ ___________.

Back 42

Viral interleukin-10
B cell
Burkitt's lymphoma

Front 43

Influenze A viruses have ___ gene segments that encode 10 polypepetides. Segment __ and ___ are prominant in causing outbreaks

Back 43

8
Segments 6 and 4

Front 44

Latent infections

Back 44

-Periods of inactivation and activation
-Usually limited pathology
-Herpes viruses

Front 45

Chronic infections

Back 45

Infectious virus can be detected for years or decades with little discernable pathology but can eventually lead to disease
-Hep B and C viruses

Front 46

Slow infections

Back 46

-Short period of acute infection followed by apparent disappearance of virus for months or years with pathology ensuing
-HIV

Front 47

Tumor viruses drive cell ________ so they can have more homes.

Back 47

proliferation

Front 48

_________ viruses, like influenza, contain multiple genetic elements that encode different genes.

Back 48

Segmented

Front 49

________ of a cell with two or more different strains of a virus can lead to the emergence of __________ viruses that have distinct characteristics. This is called ___________.

Back 49

Coinfection
Reassortant viruses
Reassortment

Front 50

The H5N1 influenza virus has subtype __ ____ segment and subtype __ ____ segment.

Back 50

5 HA
1 NA

Front 51

What are the two main methods used to study viruses?

Back 51

1. Cultivation of host cells
2. Cell culture

Front 52

Cultivation of host cells involves __________ chicken eggs that must be _________ to the virus.

Back 52

Embryonated
Suseptible

Front 53

The two main targets in cultivation of host cells are:

Back 53

1. Chorioallantoic fluid (CAF)
2. Embryo

Front 54

Step 2 of infection is:

Back 54

Entry into the cell

Front 55

Other viruses are internalized by _________.

Back 55

endocytosis

Front 56

In both fusion and endocytosis, the ________, containing the nucleic acid and viral enzymes, is ________ into the _________.

Back 56

Capsid
dumped
cytoplasm

Front 57

Step 3 is:
Step 4 is:

Back 57

Targeting to the site of replication
Uncoating
(these steps go together)

Front 58

Most DNA viruses replicate in the __________, while most RNA viruses replicate in the __________.

Back 58

DNA = Nucleus
RNA = Cytoplasm

Front 59

Some viruses ________ their dsDNA into the host cell's genome. Some viruses copy their RNA into ______, which is then integrated into the host cell's genome.

Back 59

Integrate
dsDNA

Front 60

Uncoating is caused by the dissociation of the _______ _______ from the ________ subunits that make up the capsid. This causes the capsid to ___________ and liberates the nucleic acid.

Back 60

Nucleic Acids
Protein subunits
Disintegrate

Front 61

Step 5 of infection is:

Back 61

Nucleic acid replication and protein synthesis

Front 62

If a virus is not a plus-strand it has a prepackaged, _____-encoded ____-dependant RNA pol and is termed a ______-strand virus.

Back 62

virus-encoded
RNA-dependant
Minus-strand

Front 63

In a cell culture, cells are grown attached to flasks in a ________, inoculated with the virus and within days, ________(CPE) effect can be seen.

Back 63

Monolayer
Cytopathic effect

Front 64

Prions are...
Prions cause...

Back 64

-Proteinaceous infectious particles
-spongiform encephalopathies

Front 65

Prions contain no _______ acids. They are a normal cellular protein that has ________ into a ________ protein.

Back 65

Nucleic
Misfolded
Pathogenic

Front 66

List 3 diseases caused by prions;

Back 66

1. Creutzfeldt-Jakob (from mad cows)
2. Kuru (religious consumption of brains of deceased)
3. Chronic wasting disease (deer, elk, moose)