Lecture 8.8: Virus 2 Flashcards
True or false? Viruses actively (using energy) adhere to receptors.
False. They do so passively. In fact, they have no energy source at all.
These receptors may be protein or carbohydrates.
True or false? Some viruses are required to first bind with one receptor before undergoing conformational change to expose a hydrophilic region and binding again.
True.
What are the 2 forms of viral penetration?
Enveloped viruses fuse with membranes.
Other viruses enter via endocytosis.
How are viruses uncoated from endosomes?
Triggered by low pH of vesicles which induces conformational change in viral proteins. That is, it exposes the fusion region of the virus.
Where do DNA and RNA viruses replicate?
DNA: Nucleus
RNA: Cytoplasm except for influenza, which does so in the nucleus as it requires a splicing mechanism found in the nucleus.
True or false? Early proteins tend to be non structural and late proteins structural
True
What do RNA viruses require that all other viruses are okay with?
They need RNA dependent RNA polymerases. -ve sense RNA need to bring their own in.
+ve sense RNA viruses make their own polymerase as their gene encodes for a polymerase in itself after autocleavage.
What kind of viruses have envelopes?
Only helical ones do.
What structures are non-enveloped animal viruses?
Icosahedral.
What are the different methods of release?
Budding, secretory (enclosed within golgi)
What are the four ways a virus affects cells?
Tumour inducing. Lysis. Chronic infection. Latent infection.
Viruses existing with mutations are known as what?
Quasispecies.
Describe what the drug acyclovir does.
It is a guanine analogue, it is a nucleoside (without a phosphate).
When they are added for DNA production during replication of a virus, they prohibit further addition due to their lack of phosphate. So chain terminates, infected cell dies.
