Viruses packet

Question 1

what kingdom and domain are viruses apart of?

Answer 1

none

Question 2

what’s an obligate intracellular parasite?

Answer 2

requires host cell to reproduce inside of cell

Question 3

what would make someone say that a virus is nonliving?

Answer 3

lacks cell membrane
lacks cytoplasm
lacks enzymes
lacks ATP
contains DNA or RNA (never both)
can reproduce, but not on its own

Question 4

what are the types of nucleic acid in a virus?

Answer 4

DNA viruses -single and double stranded

RNA viruses -single and double stranded

Question 5

what measurement are viruses measured at?

Answer 5

nanometers

Question 6

are viruses strain specific?

Answer 6

yes; phage typing

Question 7

what are the different shapes of viruses?

Answer 7

helical/filamentous 
polyhedral 
cuboidal
round
complex

Question 8

what is a colony of virus?

Answer 8

plaque; composed of billions of viruses originating from 1 parent virus

Question 9

what does the capsid contain?

Answer 9

protein shell

capsomeres

Question 10

what is the envelope composed of? What does it do?

Answer 10

optional, phospholipid bilyer, protects viruses from immune system

Question 11

what are spikes used for?

Answer 11

adherence

optional

Question 12

what would make someone say that a virus is living?

Answer 12

can reproduce (not by itself)
contains C, H, O, N (four basic elements)
has macromolecules (proteins and lipids)

Question 13

what are the effects of the environment on viruses?

Answer 13

extreme pH and temp

Question 14

what can Hepatitis B capable of doing?

Answer 14

withstanding boiling heat for 10 minutes

Question 15

what are chick embryos used for?

Answer 15

vaccines and to grow large number of viruses

Question 16

what are the different types of neurotrophic viruses?

Answer 16

rabies, polio, herpes virus

Question 17

what are the different types of dermatotrophic viruses?

Answer 17

herpes virus, chicken pox, measles

Question 18

what are the different types of viscerotrophic viruses?

Answer 18

hepatitis

Question 19

what are the different types of pneumotrophic viruses?

Answer 19

rhinovirus, influenza virus

Question 20

what are the cell lines pathway?

Answer 20

digestive enzymes out of kidney–separates cells–> petri dish with nutrient broth–7 days–> cell lines appear, add virus in petri dish –7 days–> plaque forms in petri dish with kidney cells

Question 21

list plaque assay method

Answer 21

E. coli B———>
T4 phage ——> PETRI DISH
melted agar —>

Question 22

what is a provirus?

Answer 22

viral DNA that’s incorporated into the host chromosome and never leaves

Question 23

What happens when a provirus remains latent?

Answer 23

No effect

Question 24

What happens when a provirus becomes active?

Answer 24

Goes into lytic (burst) cycle

Question 25

What is scrapie?

Answer 25

Prion disease- neurological disease of sheep

Question 26

What is kuru?

Answer 26

Prion disease- cannibals, mostly in women

Question 27

What is mad cow disease?

Answer 27

Prion disease- incubation is 20 years; no cure

Question 28

How do humans get mad cow disease?

Answer 28

The dead sheep that die from Scrapie are fed to cows, humans eat the cows

Question 29

What is Creutzfeldt-Jakob (CJD) disease?

Answer 29

Prion disease- genetic disease in older people (60-70yrs); makes same prion in mad cow disease

Question 30

What are the symptoms of prion diseases (sporongiform encephalopathies)?

Answer 30

Long incubation time CNS damage No immune response Brain tissue looks like a sponge

Question 31

What is the species to species barrier of the prion diseases?

Answer 31

None. It can go from one species to the next, nonstop.

Question 32

What are prions?

Answer 32

Proteinaceous infectious particle

Question 33

What are prions resistant to?

Answer 33

Heat, most disinfectants, UV light

Question 34

How do prions act as infectious agents?

Answer 34

PrP* contacts normal PrP and alters and converts normal PrP into PrP*

Question 35

What is the result of prions actin as infectious agents?

Answer 35

PrP* accumulates in brain tissue and forms plaque (spongy)

Question 36

What disease is caused by prion acting as infectious agents?

Answer 36

Spongiform encephalopathy (large vacuoles in brain)

Question 37

what happens when a provirus remains latent?

Answer 37

no effect

Question 38

what happens when a provirus becomes active?

Answer 38

goes into lytic (burst) cycle

Question 39

what happens to a latent infection over time?

Answer 39

becomes an active infection (lytic cycle) | can be spontaneous and induced

Question 40

what does a provirus convert?

Answer 40

a normal host cell into a tumor cell

Question 41

what does a provirus do?

Answer 41

introduce new viral oncogenes to host chromosome

Question 42

what is contact inhibition?

Answer 42

cells stop dividing when they contact other cells

Question 43

what is a characteristic of tumor cells?

Answer 43

loss of contact inhibition (cancer cells don't stop dividing when they have contact with other cells)

Question 44

what is a prion?

Answer 44

proteinaceous infectious particle

Question 45

what is scrapie?

Answer 45

a prion disease; a neurological disease of sheep

Question 46

what are prions resistant to?

Answer 46

heat, most disinfectants, and UV light

Question 47

what happens to lethal PrP* when it contacts normal PrP?

Answer 47

converts normal PrP into lethal PrP* (one is changed, it changes the bunch)

Question 48

what is the result of prions acting as infectious agents?

Answer 48

lethal PrP* accumulates in brain tissue and forms plaque (spongy lookin)

Question 49

what is spongiform encephalopathy? and what causes it?

Answer 49

large vacuoles develope in brain, leads to death ; prions acting as infectious agents

Question 50

do lethal PrP* undergo reproduction? how do they change normal PrP?

Answer 50

changes normal PrP by conversion, doesn't undergo reproduction

Question 51

what is Kuru?

Answer 51

cannibals; mostly in women

Question 52

how does a person get Mad Cow disease?

Answer 52

the sheep from Scrapie is fed to the cows, human eat cows; takes 20 years to incubate; no cure

Question 53

what is Creutzfeldt-Jakob disease (CJD)?

Answer 53

genetic disease in older people (60-70), makes same prions as mad cow disease

Question 54

what are the symptoms/pathology of spongiform encephalopathy?

Answer 54

long incubation time, CNS damage, no immune response, brain looks like a sponge

Question 55

what is the species to species barrier of spongiform encephalopathies?

Answer 55

can go from one species to another, doesn't stop.

Question 56

what happens in the lytic cycle?

Answer 56

burst and death of host cell, release of mature phages

Question 57

how many phases does the Lytic Cycle have?

Answer 57

5

Question 58

what is the burst time for the lytic cycle?

Answer 58

T4 phage- 60 minutes

Question 59

what is the burst size for the lytic cycle?

Answer 59

200 phages

Question 60

what happens in the lysogenic cycle?

Answer 60

host cell survives

Question 61

how many phases does the lysogenic cycle have? What are they?

Answer 61

2; Attachment phase and Penetration phase

Question 62

what happens to the prophase in the lysogenic cycle?

Answer 62

remains latent inserted into host chromosome

Question 63

what is the temperate phage?

Answer 63

phage that produces prophage in the lysogenic cycle

Question 64

what is the lysogenic cell?

Answer 64

host cell that has a prophage within its chromosome

Question 65

what is lysogenic conversion?

Answer 65

host cell acquires new characteristics due to a prophage (new genes)