Viruses & Prions Flashcards
What are 5 differences between viruses and other microorganisms?
They’re non-living, small, an obligate intracellular parasite, contain either DNA or RNA (never both) and have minimal/no enzymes or ribosomes
Capsids are:
A protein coat composed of capsomeres surounding virions
The nucleocapsid contains:
Genetic information
What is a lipid envelope?
An outer layer surrounding the capsid in some viruses
Enveloped viruses are ____ easily inactivated by disinfectants
more
Glycoproteins/spikes can be found:
Inserted in either the capsid or envelope
The functions of glycoproteins are:
Cellular attachment and recognition of binding sites in host cells
Viruses usually have a specific ____ ____
host range
The 6 DNA viruses are:
Herpesvidrae, Poxviridae, Adenoviridae, Papillomaviridae, Parvoviridae, Hepadnaviridae
What are the three main steps of viral infection?
- Attachment and penetration into host cell
- Replication of the genome
- Assembly and release of new virus
What are the two methods of penetration for viral infection?
Fusion and pinocytosis
Enveloped viruses usually penetrate the host cell by ____
fusion
During penetration, the ____ and/or ____ is removed from the virus
envelope, capsule
Virus and its nucleic acids are released into the ____ upon penetration
cytoplasm
Describe how DNA viruses replicate in host cells
- Use the host cell’s DNA polymerase to produce viral DNA
- Occurs in nucleus
Describe how RNA viruses replicate in host cells
- Uses own RNA polymerase to produce viral RNA
- Occurs in cytoplasm
Describe how RNA retroviruses replicate in host cells
- Uses own reverse transcriptase in the capsid to produce viral RNA
Replicated viral RNA/DNA have new ____
nucleocapsids
If an enveloped virus, the envelope is ____ into the host cell’s plasma membrane and ____
inserted, buds
What are the 3 outcomes of infection?
Productive/acute, latent, and chronic infection
Describe productive/acute infections
- Virus replicates
- Produces virions
- Host cell often killed = lytic infection
Describe latent infections
- Viral genome persists but doesn’t replicate
- Provirus
- Herpes, HIV
Describe chronic infections
- Virus replicates without destroying host cell
- Persists for long period of time
What are the symptoms of acute infection for chickenpox
Fever, itchy rash on trunk and head
