viruses and virology (4) (Stuart)

Question 1

Dmitri Iwanowski

Answer 1

extracts from infected tobacco plants transmit disease to others

Question 2

Loeffler & Frosch

Answer 2

repeated TMV (tobacco mosaic virus) experiment and Foot&Mouth disease

Question 3

Rous

Answer 3

tumours in chickens transmitted

Question 4

Twort & D-Herelle

Answer 4

identified bacteriophages

Question 5

serial transmission

Answer 5

transfer one bit at a time

Question 6

Norovirus

Answer 6

very infective
seems to be seasonal
vomiting and diarrhoea

Question 7

virus examples

Answer 7

norovirus
cold
flu
measles
mumps
smallpox
herpes simplex virus (cold sores)

Question 8

zoonosis

Answer 8

transmission from animals to humans

Question 9

Tobacco Mosaic Virus (TMV)

Answer 9

long thin tube

1 strand of RNA wrapped with stacks of protein spiralling downward, non-enveloped

Question 10

Poliovirus

Answer 10

non-enveloped
icosahedral shape
multiprotein subunits bind together to form outside coating

Question 11

influenze

Answer 11

enveloped (lipid bilayer) with helical nucleocaspid (how nucleic acid complement packaged in viral particle)
nucleocaspid protein, matrix protein

Question 12

human immunodeficiency virus (HIV)

Answer 12

envelopedwith icosahedral nucleocaspid
proteases, reverse transcriptases, integrase (retrovirus0, surface and transmembrane proteins, caspid proteins contain nucleic acid

Question 13

caspid protein

Answer 13

protein shell of virus

Question 14

IF VIRUS HAS….

-ve DNA
+ve DNA
+ve RNA
-ve RNA

Answer 14

encodes +ve RNA so translated into protein
encodes -ve RNA so not translated
translated directly into protein
make +ve and then translated

determine classes of viruses

Question 15

how many classes of viral particles according to Baltimore classification scheme?

Answer 15

7

Question 16

replication of -ve ssRNA viruses

Answer 16

involves double stranded replicative intermediate or translated directly

Question 17

RT

Answer 17

reverse transcriptase

Question 18

ICTV

Answer 18

international committee of the taxonomy of viruses

Question 19

tropism

Answer 19

specificity of a virus to specific host

Question 20

cellular tropism

Answer 20

HIV infects macrophages not neurons

Question 21

tissue tropism

Answer 21

influenza infects lung not brain

Question 22

host tropism

Answer 22

myxoma infects rabbits not humans

Question 23

how does HIV get into cells?

Answer 23

T cells’ C04 receptor bind to gp120 on HIV
conformational change
bind to CCR-5 chemokine receptor so membrane FUSION of host with virus membrane

Question 24

how does influenza enter cells?

Answer 24

endocytosis

globular head binds to sialic acid on membrane