Lecture 5 Flashcards
Give three facts to describe the calici virus
Causes diarrhoea
Icosahedral symmetry
Not enveloped
Ss RNA
Give three traits of the tobacco mosiac virus
Positive sense
Ss RNA
Tube like shape with a proteinaceous coat
Give three facts about the Hepatitis A virus
Hexagonal shape like honeycomb
Non enveloped
A picorna virus
Only one serotype of the virus
Give three facts about the HIV virus
Roughly spherical
Pleiomorphic
Diameter approx. 120nm
Envelope
Give three facts to describe VSV
Full name is Vesicular stomatitis indiana virus
Genome located in the centre
Helical protein coat
Envelope
Give three facts about bacteriophage T4
Head is hexagonal
It has a tail
Double stranded DNA genome
Has intron sequences
Give two facts about ebola
Helical symmetry
Causes death by blood loss
Give three facts about Rhinovirus
Cause of common cold 3' poly A tail on mRNA Picornavirus Not enveloped Icosahedral in structure
What is the problem of using electron microscopy to examine the structure of a virus?
The resolution is about 5nm and the internal components have a diameter smaller than this
When was the first atomic resolution structure of a virus done?
1978
What is a capsid?
An outer shell of a virus which protects the nucleic acid genome
What are the types of damage the capsid protects the genome from?
Physical damage
Shearing
Chemical damage
UV irradiation
Enzymatic damageWhat area of the virus is responsible for recognition of the host cell?
The outer surface
What happened in 1955 that proved that viruses spontaneously formed?
Subunits of the Tobacco mosaic virus and RNA and coat protein were incubated together and a virus was formed
What does spontaneous formation of a virus show?
That entropy favours the virus’ formation. This intrinsic stability is very important
What is a helically symmetrical capsid?
One in which the subunits are arranged in multiple discs to form a helix. It sometimes flexible and one coat protein suffices.
What is an icosahedral capsid?
The protein subunits form a hollow quasi-spherical structur enclosing the genome within
How many subunits does bacteriophage OX174 have?
60 triangular subunits
How are virus envelopes acquired?
Upon release from a cellular structure
What are the proteins in the viral envelope for?
Without them the lipid coat would be inert. Certain Glycoproteins act as the anti-receptor for the virus
Why are subunits used in viruses?
Necessity Self assembly Fidelity Economy Stabikity
