Viruses Flashcards
What is meant by “viruses are acellular”?
They need another organism to survive
Viruses come in a variety of shapes but the individual subunits are identical. True or false?
True
Do viruses generate ATP?
No
What does the structure of a virus consist of?
Protein coat (capsid)
The capsid is composed of __________
capsomeres
What are the two geometrical forms of a virus?
Icosahedral
Helical
Do all viruses have envelopes and tails?
No, some do, some don’t
Viruses only have one type of nucleic acid. What can this be?
ssDNA or dsDNA OR
ssRNA or dsRNA
How can viral replication be observed?
Observe host lysis (plaque formation)
For viruses to replicate, they require a host. True or false?
True
What are the routes of transmission for viruses?
Respiratory transmission Faecal-oral transmission Blood-borne transmission Sexual transmission Animal or insect transmission
Some viruses have affinity to specific tissues. True or false?
True
CD4+ cells are infected by ____
HIV
What happens when cells are infected by a virus?
Cell destruction
Virus-induced changes to gene expression
Immunopathogenic disease
How is influenza A virus spread?
Respiratory route
Influenza A alters cytokine expression, leading to fever. True or false?
True
Are antivirals able to enter cells infected with a virus?
Yes
How do antivirals work?
They interfere with viral nucleic acid synthesis and/or regulation
Antiviral drugs are used to treat infections caused by viruses including HIV. True or false?
False - treat infections caused by viruses other than HIV. Antiretroviral drugs are used to treat infections caused by HIV
Why is amantadine a narrow spectrum drug?
Only works against Influenza A
Amantadine is used prophylactically when a vaccine is not available. True or false?
True
Taking amantadine doesn’t stop you from getting an infection, it just reduces your recovery time. True or false?
True
Aciclovir suppresses the replication of which viruses?
HSV1
HSV2
VZV (Varicella)
Oseltamivir and Zanamivir are active against which types of influenza?
A and B
What are High Active Antiretroviral Drugs?
Include at least three medications which work in different ways to reduce the viral load
What are the three different types of TSEs?
Infectious
Sporadic
Familial
What are the characteristics of TSEs?
transmissible
relentlessly progressive and inevitably fatal
long incubation periods
no antibody response
no fever (afebrile)
neuronal vacuolation (plaques in the brain)
Prions are larger than viruses. True or false?
False - smaller
What is the normal protein in a prion?
PrPc - found at the cell surface in plasma membrane
The normal protein of a prion is easily soluble and easily digested by proteases. True or false?
True
The secondary structure of a normal protein of a prion is dominated by beta conformation. True or false?
False - alpha helices
What is the abnormal protein of a prion?
PrPsc
What is the difference between a normal and abnormal protein in a prion?
The secondary structure in an abnormal protein is dominated by beta conformations whereas in a normal protein it is dominated by alpha helices
What is a similarity between a normal and abnormal protein in a prion?
They have the same amino acid sequence and primary structure
What happens when a PrPsc contacts a PrPc?
It converts it into the abnormal form
The abnormal protein is easily digested by proteases. True or false?
False - highly resistant
What are the two different types of atypical BSE prions?
H-type
L-type
