Block D 1

Question 1

what are the 5 classes of viruses

Answer 1

-respiratory viruses
-enteric viruses
-arboviruses
-hepatitis viruses
-sexually transmitted viruses

Question 2

examples of respiratory viruses

Answer 2

influenza
rhinovirus
adenovirus
coronavirus

Question 3

how are respiratory viruses usually acquired

Answer 3

inhalation of droplets and replicated in the respiratory tract

Question 4

examples of enteric viruses

Answer 4

polio
rotavirus
reovirus
some adenovirus

Question 5

where do enteric viruses replicate

Answer 5

in the gut

Question 6

how are enteric viruses acquired

Answer 6

ingestion of faecal-contaminated material

Question 7

examples of arboviruses

Answer 7

flaviruses
bunyaviruses
some rhabdoviruses

Question 8

what do arboviruses infect

Answer 8

infects insects that ingest vertebrate blood

Question 9

where do arboviruses replicate

Answer 9

in the tissue of the insect and then transmitted to vertebrate host

Question 10

what are hepatitis viruses

Answer 10

all viruses that cause liver disease

Question 11

examples of sexually transmitted viruses

Answer 11

herpes simplex
papilloma viruses

Question 12

what is the easiest virus to grow

Answer 12

bacterial viruses

Question 13

why are plant viruses the most difficult to cultivate

Answer 13

often requires growth of the whole plant

Question 14

what can animal viruses (and some plant viruses) be cultivated in

Answer 14

tissue/cell cultues

Question 15

what does titer mean

Answer 15

number of infectious units per volume of fluid

Question 16

what is a plaque assay

Answer 16

analogous to the bacterial colony
one way to measure virus infectivity

Question 17

what are the 2 symmetries of capsid

Answer 17

helical
icosohedral

Question 18

what are capsids formed from

Answer 18

structural subunits

Question 19

what are large assemblies of capsids referred to as

Answer 19

capsomers

Question 20

what is the term given to viruses without membranes

Answer 20

naked

Question 21

what does virion consist of

Answer 21

nucleic acid packaged into a protein coat (capsid)

Question 22

what is a nucleocapsid

Answer 22

nucleic acid and protein packaged into a virus

Question 23

what do some virions contain making them critical to infection

Answer 23

enzymes

Question 24

what are the 3 enzymes that some virions contain

Answer 24

lysozyme
nucleic acid polymerases
neuraminidases

Question 25

function of lysozymes

Answer 25

makes hole in cell wall lyses bacterial cell

Question 26

what do neuraminidases do

Answer 26

cleave glycosidic bonds allows liberation of viruses from cell

Question 27

what is the Baltimore classification system

Answer 27

used to classify viruses based on their manner of mRNA synthesis

Question 28

3 stages of virus replication

Answer 28

initiation replication release

Question 29

what are the 4 stages of the initiation phase of virus rep

Answer 29

recognition attachment penetration uncoating

Question 30

what are the 4 stages of the replication stage of virus rep

Answer 30

transcription protein synthesis genome replication assembly

Question 31

what are the 2 stages of the release stage of virus rep

Answer 31

lysis and release budding and release

Question 32

in virus replication what may receptors be

Answer 32

proteins carbohydrates glycoproteins glycolipids

Question 33

in virus replication what may viral attachment be

Answer 33

capsid protein that extends from capsid glycoproteins of enveloped viruses

Question 34

what type of penetration occurs with naked viruses

Answer 34

pore mediated (viropexis)

Question 35

in virus replication what occurs when the virus is naked and enveloped

Answer 35

endocytosis

Question 36

in virus replication what occurs when the virus is enveloped

Answer 36

membrane fusion

Question 37

what does size have to do with host dependency

Answer 37

smaller the virus the more dependent on host

Question 38

what do many viruses promote

Answer 38

cell growth

Question 39

where does transcription occur in DNA viruses

Answer 39

nucleus

Question 40

what is transcription regulated by (DNA viruses)

Answer 40

by interaction of DNA binding proteins wth regions of viral genome

Question 41

what is transcribed first (DNA viruses)

Answer 41

mRNA for nonstructural proteins (early proteins)

Question 42

where is DNA replication initiated at (DNA viruses)

Answer 42

origin

Question 43

what is DNA rep said to be (DNA viruses)

Answer 43

semi conservative

Question 44

what is always formed in replication of RNA viruses

Answer 44

DSRNA replicative intermediate

Question 45

what must polymerases MUST be (RNA viruses)

Answer 45

virus encoded

Question 46

where does RNA replication occur

Answer 46

cytoplasm

Question 47

what type of viruses are more prone to mutation

Answer 47

RNA viruses

Question 48

what strand of virus is rabies

Answer 48

-ve RNA

Question 49

what does translation of viral mRNA depend on

Answer 49

host cell functions

Question 50

what can eukaryotic ribosomes not translate

Answer 50

polycistronic mRNA

Question 51

what do viruses promote (viral protein synthesis)

Answer 51

preferential translation of their mRNA