Lecture 6 - Viruses

Question 1

what type of genomes can viruses have

Answer 1

DNA = SS or DS DNA
RNA = SS or DS RNA
or
BOTH

Question 2

size range of a virus

Answer 2

0.2 - 1.5 micrometres

Question 3

name of the spikey things on outside of some viruses

Answer 3

glycoproteins

Question 4

what is a capsomere

Answer 4

tiny subunits that make up the protein coat, referred to as the capsid

Question 5

example of virus with rna genome and the mechanism it uses to replicate

Answer 5

retrovirus
replicates via DNA intermediate
then uses reverse transcriptase to translate RNA –> DNA in host cell

Question 6

example of virus with dna genome and the mechnism

Answer 6

hepadnavirus
replicates with RNA intermediate
E.g. Hep B

Question 7

vital thing that needs to be made in all viruses

Answer 7

mRNA

Question 8

what can capsid be made from

Answer 8

polymer of single protein
or several proteins

Question 9

name of virus in the extracellular state

Answer 9

virion
it is metabollicaly inert and structure is stable so genome is protected between hosts

Question 10

name process of genome being released into host

Answer 10

uncoating

Question 11

what is a virion’s membrane made of

Answer 11

host’s membrane
but can also get ‘naked’ viruses

Question 12

effects of tobacco mosaic virus and its genome

Answer 12

affects crops
chlorosis, curling, mottling mosaic dwarfing

ssRNA
Naked

Question 13

effects of polio virus and its genome

Answer 13

95% are assymptomatic
5% result in paralysis

ssRNA
Naked

Question 14

name of that crazy shaped capsid

Answer 14

icosahedral

Question 15

effects of herpes virus and its genome

Answer 15

cold sores & genital infections

anveloped and icosahedral ds DNA

Question 16

effects of coronavirus and its genome

Answer 16

sever acute respiratory syndrome

enveloped and helical ssRNA

Question 17

effects of paramyxovirus and its genome

Answer 17

measles & mumps

enveloped and helical
ssRNA

Question 18

name of flu viruses and the genome

Answer 18

orthomyxovirus
ssRNA

Question 19

name 2 of glycoprotein coat types on flu virus

Answer 19

haemagglutinin
neuraminidase
depedning on number, written like this (H5N1)

Question 20

what type of symmetry do rod viruses have

Answer 20

helical symmetry

Question 21

what is the length and width of virus (e.g. TMV) determined by

Answer 21

length = length of the RNA

width = size and packing of subunits

Question 22

how mnay faces in icosahedral symmetry

Answer 22

20 faces

Question 23

how do bacteriophages enter bacterial cell

Answer 23

lysozyme
breaks peptidoglycan

Question 24

what process does virus enter by

Answer 24

endocytosis

Question 25

what process does virus exit by

Answer 25

budding

Question 26

6 steps in virus infectious cycle

Answer 26

1) attachement and entry
2) uncoating
3) translation - making all proteins needed
4) genome replication -
5) assembly of structural subunits
6) release of mature virions from cell

Question 27

what kind of symmetry does parvovirus have

Answer 27

icosahedral