Week 3 - Microbiology Viral Structure

Question 1

Viruses - 2 types

Answer 1

Prokaryotic - bacteriophage

Eukaryotic - ex. animal viruses

Question 2

Prokaryotic vs Eukaryotic

Answer 2

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Question 3

What is a bacteriophage?

Answer 3

Bacteriophages sit on surface of cells and inject material into them

Question 4

oblicate intracellular parasites

Answer 4

Need a host to survive

Question 5

w

Answer 5

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Question 6

w

Answer 6

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Question 7

What are characteristics of virusis

Answer 7

Obligate Intracellular Parasites (they need a host)

Viral particle is DNA or RNA in a protein coat (with or with out membrane)

Outercoat protects the genetic material and facilitates adhesion/infection

Contains NO enzymes, organelles or other biosynthetic machinery

Nucleic acids code for proteins needed for viral replication

Question 8

Why are there not many anti-virals

Answer 8

Viruses have no ribosomes…

So if a drug targets inhibition of protein synthesis of virus it will also inhibit protein synthesis of the host

Question 9

x

Answer 9

…

Question 10

x

Answer 10

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Question 11

Enveloped viruses

Answer 11

Acquire membrane from host

Question 12

Naked capsid viruses

Answer 12

Consist of the nucleic material with a coat or capsid

Question 13

Viral structure is made of?

Answer 13

Envelope
Nucleocapsid/Capsid
Capsomer
Polyhedral/Helical

Question 14

Envelope

Answer 14

Gets from host

Question 15

Nucleocapsid/capsid

Answer 15

Protects DNA or RNA of virus

Question 16

Plyhedral/helical

Answer 16

Different Capsid structures

Question 17

Capsomere

Answer 17

Subunit of capsid structure

Question 18

Viroids

Answer 18

Very small single stranded circles of RNA (300 - 400 nucleotides)

Cause disease in PLANTS

Replication strategy unknown - prob through host RNA polymerase

HDV (Hep D virus) is similar to viroid

Question 19

HDV

Answer 19

Hep D virus - is similar to Viroid

Question 20

Prions

Answer 20

‘Slow virus diseases’

Resistant to:

heat inactivation (autoclaving)
radiation damage
nucleases (DNAases and RNAases) - they contain NO nucleic acid

Question 21

What can prions be inactivated by?

Answer 21

Detergents
Urea
Phenol

Question 22

What are Prions resistant to?

Answer 22

Autoclaving
Radiation
Nucleases

Question 23

Examples of Prion diseases

Answer 23

Spongiform Encephylopathies

Scrapie
Kuru
Creutzfeldt-Jacob Disease
‘Mad Cow’

Question 24

Scrapie

Answer 24

Prion disease in sheep

Question 25

Kuru

Answer 25

Human prion disease in cannibals in Papua New Guinea

Question 26

Mad Cow Disease

Answer 26

BSE - Prion disease Causes vCJD in humans

Question 27

Cruzs jacob disease

Answer 27

Human prion disease The source is unknown but it is thought to be a variant of BSE (mad cow)

Question 28

PrPc

Answer 28

Is a noromal human protein.. Function unknown When this protein folds differently (PrPsc).. It has different conformational shape that causes the proteins around it to also fold into the similar shape which leads to the disease...PRION diseases Proteases can degrade PrPc but NOT PrPsc after it folds differently...

Question 29

How is prion protein PrPsc folded differently

Answer 29

PrPc has 3 alpha helices and one beta sheet... PrPsc has 2 alpha helicies and 4 beta sheets Prion protein catalyzes formation of itself!

Question 30

What tells alot about virus?

Answer 30

DNA or RNA Capped or naked Polyhedral or helical