Viruses Flashcards
What is a virus
What are the differences between life and virus’s
What is a virion particle
What is a viral genome *
A virion is the complete, infectious form of a virus outside a host cell. It serves as the vehicle for delivering the viral genome to new host cells
Viral Genome:
The genetic material (DNA or RNA) that carries the virus’s genetic instructions for replication
What is the virion factory *
is a specialized region within an infected host cell where viral replication and assembly are concentrated
What different genome characteristics can viruses have
What are the differences between DNA and RNA virus genomes
What is a characteristic of viruses with small genomes
Are rna viruses Double or single-stranded
Are dna viruses Double or single-stranded
Give an example of a virus with a circular genome and why doesn’t it cause tumours in humans but does in humans
What is meant by negative and positive sense viruses
What is meant by segmented and non segmented viral genomes *
A segmented genome consists of multiple separate pieces of genetic material, each encoding different parts of the virus’s genetic information
A non-segmented genome is a single continuous strand of genetic material (DNA or RNA).
Give an example of a virus with a segmented genome
How does influenza evolve
What is meant by assortment *
The viral RNA-dependent RNA polymerase lacks proofreading ability, leading to frequent errors during replication - mutations
Influenza A viruses have a segmented genome (8 RNA segments).
If two different strains co-infect a cell, their gene segments can mix during viral assembly - reassortment
How are viruses visualised
What is the structure of a simple virus
What shaped virus capsids can you have
What are the characteristic of enveloped viruses
Give two examples of enveloped viruses
Bunyviridae
Filoviridae
What does it mean when a virus is host specific
What different scenarios can occur for viruses that can have more than one host (arent host specific)
What is meant by zoonotic viruses
How can you predict future zoonotic infections
How are viruses named /labelled
what is meant by a virus reservoir*
A virus reservoir is any population, organism, or environment where a virus naturally exists, replicates, and persists over time
What is the characteristic of most non human viruses
What viruses are thought to be alive
What are the characteristics of the mimivirus
Give an overview of the general virus life cycle
What are the stages of viral replication and when can virion particles be observed
What is the first step of virus life cycles
Give some examples of viruses and the receptor on the cell they bind to
Rabies - acetylcholine receptor - neurons
Simbis- laminin receptor - skeletal muscle cells
Give an example of a retrovirus
What is meant by cellular tropism for virus’s*
Cellular tropism refers to the preference or specificity of a virus for infecting particular cell types. This specificity is determined by the interaction between the virus and the host cell, influenced by the presence of suitable receptors and other factors required for viral entry, replication, and assembly.
What different mechanisms can viruses use to enter a host cell to infect it
How does HIV infect cells
How does influenza infect a cell
How does polio infect a cell
How do DNA viruses infect a cell
What are the general points of the replication of viral genomes
How do single stranded +sense RNA viruses replicate in the host cell
How do single stranded -sense RNA viruses replicate in the host cell
How do double stranded DNA viruses replicate in the host cell
How do retroviruses replicate in the host cell
What are the general characteristics of viral transcription
How is the virus capsid assembled
How are viruses with envelopes assembled *
(How do enveloped viruses exit the host cell )
How do non enveloped viruses exit the cell
Why does maturation of enveloped viruses occur after the virus exits the host cell
What is meant by a host cell being permissive and non permissive and what can it lead to
What is meant by persistent infections
What are the effects of the different types of infection on their host cells
What is meant by morphological effects
What are syncytia and how do they form
What are the possible biochemical and physiological effects of viral infection on host cells
What are the possible genetic affects of viral infection on the host cell
What is meant be an induced and innate defence of a host cell against viral infection
Give an example of an induced defence that a cell undergoes against viral infection
What different cell defence mechanisms could interferon induce against viruses
What is TIP + role + exception
What is Tetherin and TRIM5alpha and what does it do
Give an example of an innate defence
Give an example of a transforming retrovirus
RSV is a transforming retrovirus as it has captured an oncogene from its previous host , it encodes a tyrosine kinase
• viruses related to RSV (termed ALVs) do not contain oncogenes
What is the difference between RSV and ALV
Give an example of a DNA virus that can abuse cellular transformation
How does HPV usually work to replicate
How can HPV cause tumour formation
What happens when a DNA viruses full genome is integrated vs partially integrated into the host cells genome
What is the morphology of coronaviruses
How does coronaviruses genomes compare to other RNA viruses
What order is coronaviruses part of
How are coronaviruses genomes organised
What is the life cycle of coronaviruses
What is SARS-COV2
What is MERS
Where may SARS-COV2 have originated from
What are the characteristics of SARS
What is meant by the reproductive number of viruses and how does it change
How has SARS COV 2 changed over time
Why don’t all emergent viral diseases become pandemic
*
Low Human-to-Human Transmission
Mode of Transmission: Viruses transmitted through direct contact or vectors (like mosquitoes) are less likely to cause pandemics than those spread through respiratory droplets.
Restricted Host Range
Viruses emerging in remote areas may burn out before they can spread widely due to limited contact with large populations.
Some viruses thrive only in specific environmental conditions
When is R0 high , and when is it low
What is the future of SARS-COV2
What are the routes of entry for viruses
What is meant by primary and secondary viremia
What id meant by dissemination
What is meant by localised spread of a virus in the body
Give examples of viruses that disseminate via blood
Explain rabies dissemination
Explain what is meant by latency and how it occurs
What are the different viral mechanisms of latency
What is an episome *
An episome is a genetic element that can exist either as an independent DNA molecule in the cytoplasm or integrated into the host cell’s chromosome
While all episomes are plasmids, not all plasmids are episomes. The defining feature of episomes is their ability to integrate into the host genome, a property not shared by all plasmids
Give an example of latent viruses + their targets
What are viral reservoirs
What is a Quasispecies
How do viruses fight against the immune response
